Trigonometric Definition and 1000 Threads

  1. M

    Trigonometric functions and radians

    Solve the following equation giving values from -\pi to \pi: cos (2v - \frac{\pi}{3}) = \cos v Here is my attempt to solve it. As the cosine of the two is the same, the angles should also be the same leaving 2v - \frac{\pi}{3} = v + 2 \pi n Then if I move the right over to the left, I get...
  2. K

    Trigonometric Functionssimplify sin squared functions

    just looking at another question to do with trigonometric functions and I can't see how they simplify the follwing: 2sin^2x-3sinx-2=0 to (2sinx+1)(sinx-2)=0 again i prob thinking sumthin really stupid...but i can't see wat! cheers
  3. O

    Derivative of inverse hyperbolic trigonometric functions

    I'm working on a pre-freshman year math packet for college, and at one point it asks for the derivative of sinh-1(x), followed up by the derivative of ln( x + sqrt(1+x2) ). In high school, we never really covered hyperbolic trigonometry, but I have previously derived that the inverse of sinh is...
  4. E

    Can Trigonometric Series be Evaluated Using Euler-Maclaurin Sum Formula?

    Let be the series: \sum_{n} e^{if(n)} where f is a function perhaps a Polynomial ..then my question is..how can this series to be evaluated (at least approximately) ?..perhaps using Euler-Bernoulli sum formula, and another question what are they used for?, i heard in a book that Goldbach...
  5. T

    Solving trigonometric equations

    as we know that (sin(x))^2 + (cos(x))^2=1 how about (sin(3x))^2 + (cos(3x))^2 and 5sin(3x)^2 + 6cos(3x)^2?? how can we solve these problems?? thanx
  6. E

    How Can I Graph THis trigonometric Function?

    Cud u Help Me How to Graph these? y = 2 + sinx ; where x = teta y = 2sinx ; where x = teta cud u give me some ideas pls?
  7. Orion1

    Iterated trigonometric differentiation

    These are some equations that I recently developed and submitting for review. Evaluations?, comments? Iterated trigonometric differentiation: \frac{d^n}{dx^n} \sin x = \sin \left(x + \frac{n \pi}{2} \right) \frac{d^n}{dx^n} \cos x = \cos \left(x + \frac{n \pi}{2} \right) Iterated...
  8. S

    Differentiation of Inverse Trigonometric Functions

    Hey guys, I have to know how to Differentiate Inverse Trigonometric Functions in my next exam and need somewhere to study up on them. Do you know of any web sites I could read? Can't find anything on Karl's Calculus. Thanks
  9. S

    How Do You Systematically Solve the Equation 2cos²x - cos x = 0?

    Dear all, How to solve this trigonometric equation systematically? 2cos^(2) x - cos x = 0, where x ∈ [0,360] Thanks in advance
  10. T

    Trigonometric functions like sin(2x)=2sin(x)cos(x)

    Hi guyz, as we know we have some known relations in the trigonometric functions like sin(2x)=2sin(x)cos(x) and sin(x/2)=1/2-1/2 cos2x My question is are there similar formulas for arcsin and arccos? I know those only ! arcsin x =ln(ix-sqrt(1-x^2)) arccos x =ln(-ix-sqrt(1-x^2))...
  11. F

    Applying trigonometric functions to some real life situations

    I'm having some trouble with applying trigonometric functions to some real life situations, particularly this one problem in my homework. Andrea, a local gymnast, is doing timed bounces on a trampoline. The trampoline mat is 1 meter above ground level. When she bounces up, her feet reach a...
  12. P

    Trouble with Trigonometric Integral? Get Help Now!

    Haven't done integrals in such a long time and now I'm having some trouble with this question here. Any help would be appreciated. Thanks :smile: http://img331.imageshack.us/img331/4333/screen192cj.jpg
  13. P

    Solving a Trigonometric Equation: Tips and Tricks for Beginners

    I have stuck on this problem for long time sin^2 \alpha = \frac{\alpha}{2} I never meet this kind of problem before, and I have no idea about this. Could someone tell me how to solve this kind of problem? Thanks in advance. (Ans: \alpha = 1.39 rad )
  14. J

    Trigonometric Identity? - Deriving the Double Angle Formulas for Sine and Cosine

    Trigonometric Identity?? I just can't figure this out. I don't think I've covered enough material to do this. Can anyone help? I've put the entire question but I am sure all i need is a little explanation and maybe the first answer and i could do the rest. :confused: Let z =...
  15. P

    Can this trigonometric equation be solved for x_1 and x_2 in terms of \alpha?

    x_1(cos\alpha-1) + x_2sin\alpha = 0 x_1sin\alpha + x_2(-cos\alpha-1) = 0 How to solve this equation? Can anyone help me?
  16. Loren Booda

    Polynomial, trigonometric, exponential and fractal curves

    What other curves are there that cannot be described by the above? Are trigonometric functions actually a special case of exponentials with complex powers?
  17. H

    Verifying a Hard Trigonometric Identitiy ()

    My Pre-Cal teacher gave us this problem today. I have worked on it for a very long time and have goten no where :confused:. I was wondering if anyone had any ideas on how to do it, or even where to start. I started it myself with using the pythagorean idenities for the left side, then the...
  18. C

    Help with Trigonometric Simplifying

    Hi, i need help with simplifying this problem. I think it is an identity, but it looks very complex, and I wanted some other peoples thoughts/opinions. Well here goes... cos^2((pi/4)-(x-2)) - sin^2((pi/4)-(x-2)) I reduced it using the identity cos2x=cos^2x - sin^2x. I came out with...
  19. O

    Solving Trigonometric Equations

    I have a question when solving trigonometric equations. For example: Find all the solutions in the interval [0,2pi) \sin \theta \tan \theta = \sin \theta \] If you choose to divide through by \sin \theta\] we get, \tan \theta = 1\] such that \sin \theta \ne 0\] otherwise we are...
  20. S

    Struggling with Trigonometric Equations: Need Some Help?

    I'm having trouble with two problems: 2tan(x) - 2cot(x) = -3 and cos(x)^2 + sin(x) = 0 On the 2nd one, I can substitute 1-sin(x)^2 for cos(x)^2 right? I tried that, but it didn't work. And I have no clue what to do on the first one. Little help please?
  21. H

    Derive most trigonometric identities from the addition formulas

    In the same way that it is possible to derive most trigonometric identities from the addition formulas, what is the way that the difference of sines and cosines formulas were derived, such as \sin{a}-\sin{b}=2\cos{\frac{a+b}{2}}\sin{\frac{a-b}{2}} thanks, I am trying to avoid as much...
  22. S

    Can substitution be used to solve these trigonometric integrals?

    the two problems are the integral of (sec^3x)(tan x)dx and the integral of (sec^4x)(tan x)dx will substitution work for both of these problems
  23. A

    Derive a trigonometric equation for the volume of the cone

    A circular cone is inscribed in a sphere with a radius of 30cm. The semi vertical angle is theta. Derive a trigonometric equation for the volume of the cone. This has be stumped. I tried looking up proofs for the expression of the volume of a cone for inspiration but all involve calculus.
  24. D

    Limits of a Trigonometric Function

    Question: lim(x->0) for (tanx - sinx) / (sinx)^2 This is what I got: = (sinx-sinxcosx) / (cosx)(sinx)^2 = (sinx)(1-cosx) / (sinx)(sinx)(cosx) = (1 - cosx) / (sinx)(cosx) However, I can't figure out what to do from this step, as the limit still equals 0/0 at this stage.
  25. D

    Limit of a Trigonometric Function

    Question: lim(x->0) for (tanx - sinx) / (sinx)^2 This is what I got: = (sinx-sinxcosx) / (cosx)(sinx)^2 = (sinx)(1-cosx) / (sinx)(sinx)(cosx) = (1 - cosx) / (sinx)(cosx) However, I can't figure out what to do from this step, as the limit still equals 0/0 at this stage.
  26. S

    How Do You Integrate sin^6(x) Using Trigonometric Identities?

    Problem: \int sin^6 x dx Progress so far: \int (sin^2 x)^3 dx \frac{1}{8} \int (1-cos2x)^3 dx \frac 1 8 \int (1 - 3cos2x + 3cos^22x - cos^32x) dx Any help is appreciated. I can see using a half angle identity for cos^2(2x), but what do I do with the cos^3(2x)? Steve
  27. C

    What is the purpose of trigonometric identities

    As I rack my brains to solve(or atleast pretending) to prove Trig identites. What is it application in real life? :cry:
  28. A

    Understanding Periods of Trigonometric Functions with Different Frequencies

    f(x)= sin 3x - (1/2)sin x, find the period. i know the period for sin 3x is 2pi/3 and the period of sin x is 2pi but how do you subtract these? I totally forget how to do this! I mean i could find the answer with any graphing program but i want to know how to do this type of problem.
  29. C

    Solving a Trigonometric Equation: Primary to Secondary Solutions

    How do I get from the primary to the secondary solution of a trigonometric equation? This book tells me that the second angle is within -\pi \leq \theta \leq \pi, in a different quadrent, but I don't follow :\ Thanks. Edit: I got it (I think!): I can pick the correct quadrent using the...
  30. T

    Turning Equations into Trigonometric Equations

    Hello all, I have been looking up the golden ratio and found most of what I needed on mathworld. The site states that \phi \ = \ \frac{1}{2}(1+\sqrt{5}). I can see how (despite the fact that I don't understand how the ratio: \phi \ = \ \frac{AC}{BC} \ = \ \frac{AB}{AC} is formed but...
  31. H

    Why Does Differentiating y=sin(pi*x) Result in y'=cos(pi*x)*pi?

    When y=sin(pi*x), why does y'=cos(pi*x)*pi, not y'=cos(pi*x)? hk
  32. J

    Simultaneous trigonometric equations

    I am looking for help in solving a pair of simultaneous equations. I have not come across any maths book that solves trigonometric ones. I was wondering if I could get a step by step solution. Thanking you in advance for your time: 5.4=10cos(x) + 13.41cos(y) ....(i) 0=10sin(x) +...
  33. Pyrrhus

    Calculating Angle C in Vertical Plane: Trigonometric Problem in Dynamics Book

    Hello, I'm in need of a hint or few pointers on how to calculate the angle C of the picture attached. I've already calculated y. I was doing a few problems in this Dynamics book, i bought recently, and the ascention angle (angle C) is beating me :eek: "The airplane C is being tracked...
  34. L

    Pre-Test on Trigonometric Equations and Applications

    I have a math test on the chapter on Tuesday, and my teacher handed out the pre-test on Thursday. There are a few problems I am totally stumped on, and figured the math geniuses here could give me some help. Some I can get somewhere with, some I don't know where to begin. Here is one...
  35. N

    Simple Integral w/ Trigonometric Substitution

    Hello everyone, I am having some trouble with an integral. \int \sqrt{x^2 - 1} dx so far: x = sec \theta \frac{dx}{d \theta} = sec \theta tan \theta dx = sec \theta tan \theta d\theta now we substitute: \int \sqrt{x^2 - 1} dx = \int \sqrt{sec^2 \theta - 1} sec \theta tan...
  36. C

    What is the correct answer for this trigonometric improper integral?

    Here's a integral where I have to use trigonometric substitution but I can't get the right answer. [int a=0 b=3] 1/(sqrt[9-x^2]) dx I did the limit as t approches 3 from the left. Then i did my trigonometric substitution, and it gives me arcsin(x/3). Then i computed what i had...
  37. N

    Solving a Trigonometric Equation

    How would you solve for \alpha in the following equation? 4=\cos(\alpha)+\cos^2(\alpha)+\cos^4(\alpha)
  38. L

    Chapter Summary: Trigonometric Functions

    The problem reads: Find \sin\theta and \cos\theta Part a gives me the coordinates \left(-1,1\right) The triangle I got had the x-length as -1, while the y-length was 1. The hypotenuse I got was \sqrt{2} Since \sin is \frac{opposite}{hypotenuse} I got \sin\theta=\frac{1}{\sqrt{2}}...
  39. A

    How Do You Integrate Using Trigonometric Substitution?

    \int x^3\sqrt{4-9x^2}dx I tried to use x=\frac{2}{3}\cos{(x)} but it just left me with \int \sin^3{(x)}\cos^2{(x)}dx Any suggestions? Thanks for your help.
  40. L

    Inverse Trigonometric Function Problems

    The math book I have does a pretty terrible job explaining this to me, because I am absolutely stumped as to why I get every question wrong in two sections: finding values of each expression in radians (can often be given in terms of ?) and finding approximate/exact values of the expressions...
  41. D

    Is there an easier approach for solving trigonometric identities?

    I'm having problems with it at school lately, I am not going to layout every single problem and ask for help. I am just wondering if there is a better approach to it rather than trying to solve one side in order to get it to equal the other side. For example, sin^2 x + cos^2 x = -cos^2 x - sin^2...
  42. D

    Graphing Trigonometric Functions Question

    Ok I can graph sin(x) , cos(x) , and tan(x) pretty easily, but I'm having a hard time graphing the csc, sec, and cot ones. For the first three I just found the values of pi/2 pi 3pi/2 and 2pi. So for example pi/2 for sin(x) would be sin 90 or sin pi/2 which is equal to 1. I then just put a...
  43. C

    How Do I Solve Complex Trigonometric Identities?

    I can, for the mort part, understand how to derive and "proof" most of my Identity work, but some of the more complex (in my feeble opinion) problems give me quite a bit of trouble. Can anyone explain these? "Use the fundamental identities to simplify to sines and cosines: tan(^2)x -...
  44. M

    Periods of Trigonometric Functions

    Here are two general questions How would you find the period of: sin(2Pi*t)+sin(4Pi*t) or cos(3t)sin(2t) Thanks
  45. P

    How Do You Prove This Trigonometric Identity?

    Hi... I need help solving this problem. I don't know what to do... Proove that \frac{cos^2\theta - sin^2\theta}{cos^2\theta+sin\theta cos\theta} = 1 - tan\theta I tried to cross out cos^2 on the top with the one at the bottom... also tried messing around with the values (cos^2x = 1 -...
  46. C

    How do I solve a trigonometric equation on a given interval?

    Hello all Just refreshing in maths, and want to know if I am doing this correctly: Solve the equation \sin x = 0.2 on the interval 0 \leq x < 2\pi . I took \arcsin(0.2) , however how do you solve for all solutions in the interval? (i.e what if the interval had been 0 \leq x < \pi...
  47. T

    I hate Trigonometric Subsitution

    How would you do \int (1-x^2)^{3/2} after you get to the point where you have made the triangle and you have x=sin\theta and dx=cos\theta
  48. M

    Trigonometric Functions - Confusing question

    What equation in the form y=sin(theta)+c best models the dtat in the chart below... ____________________________________ (theta)radians : 1 : pi/2 : pi : 3pi/2 : 2pi ______________________________________ y-------------: 2 :--3--:-2-:-1----:--2 __________________________________ I am...
  49. A

    Parsecs, trigonometric parallax and light years

    Hey I'm really confused about these things above (well except for light years). How would you get a distance in parsecs and in light years if there was an annual parallax of say 0.2 arc seconds. I'm just revising for exams but am really confused now! Thanks.
  50. V

    Adding Trigonometric Functions: Get the Answer Here!

    Hi, wat would you get if you add these: 3cos(600*pi*t) + 5sin(1000*pi*t - 45degrees) + 5sin(1200*pi*t)? thanks in advance...
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