What is Theta: Definition and 333 Discussions

Theta (UK: , US: ; uppercase Θ or ϴ, lowercase θ or ϑ; Ancient Greek: θῆτα thē̂ta [tʰɛ̂ːta]; Modern: θήτα thī́ta [ˈθita]) is the eighth letter of the Greek alphabet, derived from the Phoenician letter Teth . In the system of Greek numerals it has the value 9.

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  1. D

    Need clarification on Limits/Big-Oh/Big Omega/Big Theta

    I have a Quiz on this Friday on Big-Oh and stuff, its an algorithm course so we weren't taught anything about Limits and stuff and yet we have to use them... I tried reading up on Limits abit but I really don't understand a thing or rather I don't have time to go through everything as its not...
  2. JJBladester

    Tetherball - find theta and tension

    Homework Statement A 450-g tetherball A is moving along a horizontal circular path at a constant speed of 4m/s. Determine (a) the angle θ that the cord forms with pole BC, (b) the tension in the cord. Homework Equations \sum F_{y}=ma_{y} \sum F_{n}=ma_{n}=m\frac{v^{2}}{r} The...
  3. L

    Dynamics rotating disk, solve for r and theta magnitudes

    Homework Statement A screen clipping of the problem is here: http://img529.imageshack.us/img529/1738/dynamicsquestion2.jpg We have a circular disk that roates about its center, 0, with a constant angular velocity \omega (\omega = \dot{\theta}. The disk carries two spring-loaded plungers...
  4. Q

    Solving for F3 Magnitude and Theta Given F1 and F2

    The three concurrent forces acting on the post produce a resultant force of 0. If F2 = 0.5F1, and F1 is to be 90 degrees from F2 as shown, determine the required magnitude F3 expressed in terms of F1 and the angle theta. I am having no troubles finding the magnitude of F3, however, I am...
  5. atomqwerty

    Calculating Theta for Lowest Wavelength Electron Beam

    Homework Statement An electron beam (energy 119,9 eV) contacts perpendicularly on a Ni plate, with interatomic spacing d= 0,215 nm. At which angle Theta will be obtained an electron beam with the lower wavelenght possible? Homework Equations n\lambda=d sin(\theta) (Bragg's for...
  6. C

    How to integrate Acos(wt + theta) ?

    How do you integrate Acos(\omegat + \theta) ? Where A is the amplitude, omega is angular velocity, and theta is position? I have no idea what to do. Should I U substitute?
  7. G

    Heat equation - theta function?

    du/dt=d2u/dx2 Show that u(x,t)=(t^a) * theta(xi) where xi=x/sqrt(t) and a is a constant, then theta(xi) satisfys the ODE a*theta - 0.5 * xi * dtheta/dxi = d2theta/dxi2 Not sure how to start this. Any help most appreciated (sorry if question isn't easy to ready)
  8. E

    What is the general angle of theta?

    Homework Statement Two plane mirrors are joined along side at a right angle. Both are perpendicular to the table top, like walls meeting at a corner. For a general angle of theta, determine the direction of the reflected ray which leaves the double mirror? Homework Equations n/a...
  9. C

    Solve for Theta: 160cosx/cos40 + 160sinx - 200 = 0

    http://photoshare.shaw.ca/image/6/8/e/231110/q-0.jpg I can't find theta. Anyone help me out here? x=theta I've tried making Fab=(160cosx)/cos40 Then plugging it in into the second equation, we get 160cosxtan40+160sinx-200=0 160(cosxtan40+sinx)=200 cosxtan40+sinx=1.25 Is there a trig...
  10. S

    How to pick theta while resolving vector.

    1 -------------------------------------------------------------------------------- 2 how to pick theta (angle between the vector and the component) above two which one is the right choice. I'm confused regarding choosing (theta).. what are the criteria that to be considered while...
  11. A

    QCD theta angle and Neutron electric dipole moment

    Dear all I have done some studies trying to understand the relation between the QCD theta angle and neutron electric dipole moment. General, the QCD vacuum produces the term L_{\theta} = \theta g_s^2\: G_a^{\mu\nu} \, G^a_{\mu\nu} this I can derive! I have studied Srednicki ch 93, Ramond...
  12. M

    Solving Trig Theta Question: 1/sin(theta)-cos(theta)/sin(theta)

    Homework Statement I don't understand the step the math book took to convert sin(theta)/sin(theta)-cos(theta) to 1/sin(theta)-cos(theta)/sin(theta) Homework Equations The Attempt at a Solution
  13. M

    Unraveling the Mystery of Theta: Solving Cot(2theta) = 2

    what is Theta? Cot (2theta) = 2 I have no idea how to get the answer. algebraically or in my calculator
  14. A

    How to Prove that A*B= |A||B|cos theta

    Homework Statement Prove that A*B = |A||B|cos theta Homework Equations Law of cosines: c^2= a^2 + b^2 - 2abcostheta Property of a dot product; x*x=x^2 Replace c^2, a^2, and b^2 with dot product The Attempt at a Solution c*c=a*a+b*b-2abcostheta since c=a-b c*c= (a-b) * (a-b) c*c=...
  15. H

    Solving equations in sin and cos theta

    Hi, I have been trying to solve some mechanics problems and I can come up with the right equation, but I don't know how to solve it... For example: 490.5cos(theta) - 3600cos(theta)sin(theta) + 1800sin(theta) = 0 i need to solve for theta here its one equation and one unknown...
  16. J

    What is the angle theta between vectors

    Homework Statement What is the angle theta between vectors vec A and vec B if vec A = 4 -3 and vec B = -2 + 5? Homework Equations arccos((a dot b)/(|a||b|)) The Attempt at a Solution 4*-2+-3*5=-23 sqrt(4^2+-3^2)*sqrt(-2^2+5^2)=10.39 arc not sure what i am doing wrong but...
  17. C

    Find force parallel to ramp given mass and theta?

    Homework Statement There's a block on a ramp. The block weighs 48.9 kg and the ramp's theta (the angle the ramp makes to the ground) is 45. Assumng gravity is 9.8 m/s^2, how would i find the force of the block parallell to the ramp?Homework Equations Um..maybe F=(mu)(m)(g) F=(mu)(normal force)...
  18. E

    Proving: limit (as theta approaches zero) of sin(theta)/(theta) = 1

    Homework Statement show that the limit as h approaches zero of ((cosh-1)/h) = 0. Homework Equations *The bold numbers preceding each line are simply line numbers, they are not apart of the equations.* 1 lim (as h approaches 0) of ((cosh - 1)/h) 2 = lim (as h approaches 0) of...
  19. R

    Solving for Theta: A Physics-Math Dilemma

    Homework Statement This is originally from a physics problem but it's more of a math question. How do I solve for theta? Homework Equations 400 - Tcos(theta) = 0 -200 + Tsin(theta) = 0 Using those equations, I need to solve for theta. Also, knowing that tan(theta) =...
  20. R

    Evaluating Electric Dipole Potential: qd cos \theta?

    Hello The electric dipole potential is V (\textbf{r}) = \frac{1}{4\pi\epsilon_o} \frac{\textbf{p}\bullet \hat{r} }{r^2} I am trying to figure out the algebra in my book. How do you evaluate the scalar product of the dipole moment and the unit vector in the above equation? I get qd...
  21. G

    Solving Sin theta Questions: An Example

    Homework Statement sorry if the title is not that descriptive Homework Equations i is the imaginary number e is 2.7... x is any anlgle in radians that is... um see the example I explain it sin x = +/- i/2 (1/e^(ix) +/- e^(ix)) I will use a example in atempt at a solution to show...
  22. G

    Where Can I Find a Table of Exact Values for sin(theta)?

    Homework Statement Does anyone know were I can find a table on the internet of the exact values of sin theta were theta is any whole angle from zero to ninety degrees Example sin 0 degrees sin 1 degrees sin 2 sin 3 sin 4 sin 5 ... sin 90 Homework Equations The Attempt at...
  23. L

    Finding the Optimal Angle for a Baseball to Return to its Release Point

    Homework Statement A boy throws a ball upward with a speed of vo= 12m/s. The wind imparts a horizontal acceleration of 0.4m/s^2 to the left. At what angle theta must the ball be thrown so that it returns to the point of release. (assuming wind does not affect vertical motion. Homework...
  24. V

    Exploring the Behavior of r=abs(sin n theta)

    Homework Statement Describe the behavior of r= abs(sin n theta) where n is a positive integer Homework Equations N/A The Attempt at a Solution I have no idea how to do this
  25. ╔(σ_σ)╝

    Obtain the forumal of cos( theta 1 + theta2) .

    Obtain the forumal of cos( theta 1 + theta2)... This should be a very basic question. I'm reviewing some linear algebra for my Field theory course but there is a question that I'm suck on. It says (a) Prove that P = cos\theta i sin\theta j and Q = cos\phi i sin\phi j are unit vectors in the...
  26. M

    What is her speed when she is at an angle theta?

    Homework Statement a snowboader is resting atop a large snowball with radius R when she begins to slide off the frictionless surface a)what is her speed when she is at an angle theta? b)find the maximum speed she can have without losing contact with the surface? c)at what angle will she...
  27. M

    Solving for Theta in the Interval 0<θ<360

    Homework Statement How do I solve for theta here: √13 Sin(θ-56.31)=1 in the interval 0< θ <360 2. The attempt at a solution sin (θ - 56.31) = 1/√13 sin (θ - 56.31) = sin ( 16.102 ) => θ - 56.31 = 16.102 Hence θ = 72.412 or θ - 56.31 = 180 - 16.102 θ - 56.31 = 163.898
  28. T

    Alpha and theta represent the same known or unknown angle?

    I was wondering in terms of a mathematical approach to physics, whether alpha and theta represent the same known or unknown angle in the triangles. Ex.. Vi = vo(sin)(theta) or Vi = vo(sin)(alpha)
  29. P

    Finding the applied force with theta, A, M, and Mu as givens?

    Homework Statement What must be the applied force (25 degrees above the horizontal) in order to accelerate a block at 1.1 m/s^2, if the mass is 2kg and the coefficient of kinetic friction is .3?Homework Equations F(net y)=Fn + Fav - W Ff = μ x Fn F(net x)=Fah-FfThe Attempt at a Solution I've...
  30. M

    Riemann-Siegel Theta Function Approximation

    This is my first post on the physicsforums so go easy on me :) I am writing a simple program to generate the zero's of the Riemann zeta function accurately. However I need the first say, ten terms of the theta function \theta\left(x\right) =...
  31. L

    Finding tangential speed to maintain an angle theta

    1. What tangential speed, v, must the bob have so that it moves in a horizontal circle with the string always making an angle theta from the vertical? Express your answer in terms of some or all of the variables m, L, and theta, as well as the acceleration due to gravity g. 2. I...
  32. A

    Finding Expression for Theta with Flywheel and Piston Movement

    Hi I am struglling to work out the expression for theta=f(x) for a piston, that moves linearly by a distance of x along the inside of the cylinder, and is attached to a conrod of length l, whose other end is at a radius r on a fly wheel. I want an expression for the angle theta that the fly...
  33. G

    Find Accel. of Cart from Mass m & Theta

    Homework Statement http://img188.imageshack.us/img188/9897/73266226.png The problem is to create an equation to find the acceleration of the cart based upon theta. All that is given is the ball hanging is known as mass m. Homework Equations f=ma f=\frac{mv^{2}}{r} The Attempt at a...
  34. K

    Finding weight with force and theta

    Homework Statement What must W be when the force directed along the leg is 26.0N http://session.masteringphysics.com/problemAsset/1012378/6/image5.42.jpg Homework Equations \SigmaF=ma=mg The Attempt at a Solution I used the two angles and drew the y-axis down from the top downward...
  35. I

    Only given displacement vector and initial speed, solve for theta

    Homework Statement A ball is thrown with a speed of 70m/s and hits the top of a wall which is 20m tall and 100m away. Find the angle that the ball was thrown at Homework Equations d= V0xt + 1/2 a t^2 a = Vf-V0/t sin^2(theta) = 1 - cos^2 (theta) The Attempt at a Solution I found...
  36. G

    Solving for Theta and Phi in Direction of Propagation | Homework Statement

    Homework Statement The direction of propagation is defined as ex=sin(theta)cos(phi), ey=sin(theta)sin(phi), ez=cos(theta). What are the values of theta and phi characterizing the direction of propagation? Homework Equations We have a point in space with the coordinates...
  37. G

    Solving Schrodinger Equation in Two Dimension, r and theta

    Homework Statement It's a two-part problem, the first part was deriving a Schrodinger equation from when x = r cos(theta) and y = r sin(theta) I got: -\frac{\hbar^2}{2m}[\frac{\partial^2}{\partial...
  38. Y

    Exploring the Relation of Theta in Inclined Planes

    Homework Statement By what relation/reasoning are these two angles, theta, the same? http://img198.imageshack.us/img198/6273/inclinedplane.jpg
  39. C

    Finding the Angle with Arctan: A Manual Approach

    Homework Statement http://carlodm.com/images/mth.png ** Note: The above is from a PRACTICE question for my course. Homework Equations arctan x = (theta) The Attempt at a Solution So. (-3,6) is in Quadrant 2. To solve for this angle we use: (pi) + arctan (-6/2) = (pi)...
  40. D

    Projectile Motion & Theta: Finding Tan (Theta) Using Equations of Motion

    Homework Statement A projectile is launched from O with speed u at angle theta to the horizontal. In its subsequent trajectory it just clears two obstacles of height h at horizontal distances d and 2d from O, respectively. http://img403.imageshack.us/img403/4369/projectile.jpg Show...
  41. K

    What is the angle of a ramp given a marble's velocity and time of descent?

    Homework Statement This was actually a lab for class today. Basically, a marble rolls down a 2.26m slope, in 3.12s. Find the angle of the slope. Assume there is no friction.Homework Equations v=d/t a=v t a=g sin (theta)The Attempt at a Solution v=2.26/3.12 = 0.724m/s since that is Avg. V...
  42. jinksys

    Finding the Bounds of Theta for a Double Integral

    Example: Use a double integral to find the area of the region: One loop of the rose r = Cos[3 theta] Finding the bounds of r is easy, 0 to Cos[3x]. However, I usually get the bounds of theta wrong. How do I find the bounds of theta without using a graphing calculator and guessing. The...
  43. T

    Maximal theta given the coefficient of kinetic friction

    Homework Statement While moving in, a new homeowner is pushing a box across the floor at a constant velocity. The coefficient of kinetic friction between the box and the floor is 0.410. The pushing force is directed downward at an angle theta below the horizontal. When theta is greater than...
  44. T

    Projectile motion given theta and x

    Homework Statement An Olympic long jumper leaves the ground at an angle of 23o and travels through the air for a horizontal distance of 8.7m before landing. What is the takeoff speed of the jumper? Homework Equations 8.7m = cos(23o)Vot y = sin(23o)t + (1/2)(-9.8m/s2)t2 0m2/s2 =...
  45. S

    Inequality involving theta and sin(theta)

    Homework Statement I'm trying to prove the following inequality for 0\leq \theta\leq\frac{\pi}{2} \frac{2}{\pi} \theta \leq\sin\theta Homework Equations 0 \leq \theta\leq\frac{\pi}{2} 0\leq \frac{2}{\pi}\theta\leq 1 The Attempt at a Solution I've looked at the limit...
  46. P

    Writing sin^2 theta * Sin 2 phi in terms of spherical Harmonics

    I am trying to write the term "Sin^2 theta * Sin 2 phi" in terms of spherical Harmonics (they form a combination of Y(2,-2) and Y(2,2)) but the term I get contains the imaginary number 'i'. Am I doing something wrong.. In fact this term is a part of a Hamiltonian and when I get the eigenvalues I...
  47. I

    Prove using de moivre's theorem of I=cos^2n theta

    Homework Statement Use de Moivre's Theorem and the result that integral (with limits pi, 0) of cos[nx]dx = 0 for all non-zero integers of n. when n does equal 0 the answer is 1. [this i proved in the first section of the qu using logic and limits(x->0). so we need to prove that...
  48. L

    Investigating the Relationship Between Max Theta and Period in a Simple Pendulum

    I am working on my lab report for the simple pendulum and we did an experiment where we increased the max theta in increments of 5 degrees, while keeping the length of the sting the same. We started from 5 degrees and went to 45 degrees. For some reason the periods seem to increase slighty as...
  49. P

    Why is this true about the angle theta

    Homework Statement From my notes: Why is: V_{e} \times sin \Theta \cong V_{e}\Theta ? The only thing I know is that the assumption: \Theta \rightarrow 0 has been made, but that doesn't make the above equation clear to me... Thanks in advance!
  50. J

    Quantifying a Picture: Calculating D & theta

    Homework Statement I'm supposed to quantify the picture below and show how to find D and the angle theta. http://img10.imageshack.us/img10/7079/labg.jpg Homework Equations none i can think of The Attempt at a Solution I guess S and H are the same. I really can't think of a...
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