Expression Definition and 999 Threads

ln(-1)/i=pi this equation does not use limits or integrals, as you can see, but it does involve imaginary numbers. Does this make it an open expression, or does the fact that it uses i not matter?

So is there any set of defined rules that help in the simplification of regular expressions? Because till now I would simply try and look at the patterns and see whether this or that simplified version would generate the same.Intuitive, but now always fast or correcct. So is there any...

Homework Statement Find dP/dt of 2048000(t^2)(e^1600t)+5120t(e^-1600t)+3.2(e^-1600t) Homework Equations The Attempt at a Solution 2048000(2t(e^-1600t)-1600(t^2)(e^-1600t))+5120((e^-1600t)-1600(e^-1600t))+3.2(-1600(e^-1600t)) After moving the t over to simply the first part and...

Homework Statement hi I'm new and thanks in advance! I'm trying to work out a problem I've been given but having difficulties! I am given a scope for the current in a capacitor and I'm trying to determine the expression of charge in the capacitor firstly, then when t = 10ms Homework...

Hi all, Anybody pls help me to convert cosmic time to conformal time (numerically)... is there any analytical expression for conformal time, \tau , except d\tau=dt/a(t) ? can we approximate \tau \approx -1/aH ?? pls help... Anuradha

Here's the question: Let f be the function satisfying f'(x)=x\sqrt{f(x)} for all real numbers where f(3)=25. a. Find f''(3) b. Write an expression for y-f(x0 by solving the differential equation \frac{dy}{dx} = x\sqrt{y} with the initial condition of f(3)=25. For a, I got...

Homework Statement Expression is p^3-(x^2+xy+y^2)p+xy^2+x^2y=0 where ^ shows power Homework Equations The Attempt at a Solution the solution is (p-x)(p-y)(p+x+y)=0

Homework Statement I have 2 charges: Q1 = 300 uC located at (1, -1, -3) m Q2 = ?? uC located at (3, -3, -2) m Q1 feels a force from Q2 of F1=(8i - 8j + 4k) N 1. Find Q2 2. Find the expression of the E-Field at (3, -3, -2) m (at Q2) Homework Equations F=(k|Q1*Q2|) / r^2 E=(k|q|)...

a.cos(wt) + b.sin(wt) = M.cos(wt + ϕ) Can you give me M and ϕ in terms of a and b?

Hi, I am doing an experiment. I am heating a sample and changing a temperature on one surface of the sample as a sine function of time. Measuring heat flux I am trying to predict heat response of the sample. After some sine cycles heat response is in every next sine cycle the same. How do you...

I'm going over the Landau's Mechanics, and can't get over two hurdles. The first is the following(I'm not good with latex here, so please bear with me): Landau asserts that the action S' between t1 and t2 of a Lagrangian L such that L is a function of (q+dq) and (q'+dq') minus the action S...

Hi! This is my first post, so i apologise if i leave out any information. I need to derive an expression for the theoretical velocity of flow in an open channel using the Bernoulli Equation. I realize it is probably a simple question but i am sort of a beginner. Any help appreciated...

Homework Statement Write the Trigonometric Expression as an algebraic expression. cos(2arccos 2x) Homework Equations Probably the inverse properties, I'm not sure. The Attempt at a Solution I know I can rewrite this equation as. u= arccos 2x cos(2cos u=2x) I can also...

Ok, I have an Expression which is attached and it needs simplifying. What I have done is got 12logx But I don't think this is correct. Another possible place I got to is logx4/logx1/3 Which one is it?

Simplify the attached expression using any relevant logarithmic rules I haven't really done much with logarithms, so i didnt know where to start?

not actually homework, but things I need to know: 1: simplify the expression e^{a ln b} (write it in a way that dosen't involve logarithims) i want to prove the identities: lnab = lna + lnb lna^b = blna \frac{d}{dx}lnx = \frac{1}{x} i also want to derive the useful assumption...

I'm finding the percent error in a S.R. problem and getting a really small number. How can I find the exact percentage? This is the result that needs to be simplified: 6.7x10^(-16) / (1 + 6.7x10^(-16)) If I do an order of magnitude approximation, then the bottom becomes 1, but that will...

If I take e^ln|x|, do I get x or |x|?

I have been asked to simplify this one: 12x3 + 8x2 / 6x2 + 4x By factoring it out I have simplified it to 4x2 / 2x Is there anything I can do to simplify it further? I know the rules of dividing powers and hence if it was 4x2 / 4x I know I could simplify it to to 4x (subtract the...

How can I simplify this expression? As it is already factorised (factored) I do not see what else I can do to simplify it. x(9x+2) / x3(x-2) The only thing that I can think of is if I unfactorise everything to give the following:(although it doesn't seem to be very simplified from the...

Are there any theorems concerning this expression \frac{1}{z}f\left(\frac{1}{z}\right). I appreciate posts of any theorems you can think of.

I know this expression should return a Gaussian distribution but I can't get Mathematica to simplify the integral. What am I missing? \text{Simplify}\left[\frac{\text{Product}\left[\text{PDF}\left[\text{NormalDistribution}[y,\sigma...

Hi, Will anybody help me to find the maximum of the following expression: |\cos^m\theta_1 (c\cos^n\theta_2+se^{i(\gamma-n\lambda_2)}\sin^n\theta_2)+e^{-im\lambda_1}\sin^m\theta_1 (\pm ce^{-in\lambda_2}\sin^n\theta_2+se^{i\gamma}\cos^n\theta_2)|^2 where m,n\ge 2 are fixed positive...

freal Loops? Hi everybody.. I have a question. Recently, I'm using g95 to run my Fortran 95 program. But it occur an error, which is: REAL expression in DO loop at <1> - to enable REAL loop parameters use -freal-loops What is freal loop exactly? and How to solve this problem...

Homework Statement By first expressing the general term in partial fractions, find an expression in terms of n for summation of r=2 to n ( 1 / (r^2 - 1) ). Hence show that summation of r=1 to n ( 1 / r^2) i less than 7/4 for all values of n Homework Equations The Attempt at a...

Homework Statement Derive an expression for the total energy required to asemble a sphere of charge corresponding to a nucleus of atomic number Z and radius R. Assume the nucleus is a sphere of uniform volume charge density \rho Homework Equations \rho = mass / volume = 3Am / 4*pi*R3...

it is given that R1=R2 http://i43.tinypic.com/b8359w.jpg i used voltage divider i tried to calculate it by taking v1 as the midle poit of the left brench and v2 as the middle point of the of the other branch so Vout=V_s/2 -Vs[r/(r+1/jwc )=v_s/2(1-rjwc/2(rjwc+1)) i can't get the...

it is given that R1=R2 http://i43.tinypic.com/b8359w.jpg i used voltage divider i tried to calculate it by taking v1 as the midle poit of the left brench and v2 as the middle point of the of the other branch so Vout=V_s/2 -Vs[r/(r+1/jwc )=v_s/2(1-rjwc/2(rjwc+1)) i can't get the...

Homework Statement Aqueous solutions of hypochlorous acid, HOCl, can be unstable due to the reaction: 2HOCl <--> Cl- + ClO2- + 2H+ (c) Write out the balanced reaction appropriate to basic solution corresponding to the reaction given above. Homework Equations K =...

Homework Statement Write the partial fraction decomposition of the rational expression. Check your result algebraically. (x2 – 7x + 16)/[(x + 2)(x2 – 4x + 5)] The Attempt at a Solution [A/(x+2)] + [(Bx+C)/(x2-4x+5)] x2-7x+16= A(X2-4x+5)+(Bx+C)(x+2)...

Homework Statement cos(2 * arcsin(2x)) Use a triangle to simplify each expression. Where application, state the range of x's for which the simplification holds. Homework Equations cos(2t) = cos^2(t) - sin^2(t) = 1-2sin^2(t) = 2cos^2(t) - 1 The Attempt at a Solution My attempt was the...

Homework Statement Use double-angle and addition formulæ and other relations for trigonometrical functions to find an expression for sin(3x) in terms of sin x alone. My problem is I don't know what is meant by "find an expression for sin(3x) in terms of sin x alone.". I know the relevant...

How do I calculate the limit: lim x-> infinity ((2x+1)^13(3x-7)^17)/((3x+5)^30) Should I use the binomial theorem to open it up?

When we are resolving a periodic piecewise continuous function in a fouriers series of harmonic terms, as follows: f(x)= a0/2 +Σancos nΠx/L + Σ bnsin nΠx/L, period 2L we are essentially expressing a sectionally discontinuous function (with finite no of such finite discontinuities, if at...

Homework Statement Consider the power series. sigma (n=1 to infinity) x^n / [n(n+1)] if f(x) = sigma x^n / [n(n+1)], then compute a closed-form expression for f(x). It says: "Hint: let g(x) = x * f(x) and compute g''(x). Integrate this twice to get back to g(x) and hence derive...

Hi, I have: \frac{a}{b+a+s} + \frac{c*b}{(b+a+s)(c+s)} I can rearrange that to: \frac{a-c}{b+a-c} * \frac{b+a}{b+a+s} + \frac{b}{b+a-c} * \frac{c}{c+s} Is this correct? If so, can someone tell me why the +s changes into a -c?

Homework Statement Consider the vector \vec A whose origin is \vec r. 1)Express the vector \vec A in a basis of Cartesian coordinates, cylindrical and spherical ones. 2)Repeat part 1) if the origin is \vec r + \vec r_0. Homework Equations None given. The Attempt at a Solution 1)In...

f(z) = SUM [(-1)n Where SUM = sum from n=0 to infinity Looks to me like there isn't but there must be a simpler way to write that. Thanks

Homework Statement I have two sets E and L. I have to show that E is a subset of L, using only complement, union and the empty set. I.e. all members of E also have to be members or L, but L may contain members not included in E.Homework Equations The Attempt at a Solution Am I right in...

the expression for the magnetic flux changing area is : change in m.flux=B.dA and for varying magnetic field change in m.flux=dB.A but for when the both is changing then what will the expression

Homework Statement Sorry if the question sounds a bit off, i wasnt quite sure how to word it. My math question is: given the expression Sn=n^2 + 2n, determine an expression, in simplified form, for Sn-1 in terms of n. Homework Equations NA (i don't think there are any equations for...

p = 4 q = -2 r = 3 s = -5 on that basis, evaluate this expression: 3r - 3p + 5q I make it to be -7 (15 - 12 + (-10) But my math book says the answer is -13. Can anyone explain where I have gone wrong? Thanks

Homework Statement Decompose the rational expression into a sum of partial fractions: (x+1)/(3(x-2)2) I am familiar with the method of decomposing fractions into a sum of partials fractions (solving for A, B, C, etc.). What is confusing me is the coefficient 3 in the denominator. Do I...

In R^3 I have two vectors a and b and the operator D = (d/dx,d/dy,d/dz) What is the interpretation/ picture of (aD)b - (bD)a? This is another vector.

I write MATLAB program on my computer but when I copy the file to another computer and press F5 to run, there is a message 'unexpected MATLAB expression' what should I do?

I write MATLAB program on my computer but when I copy the file to another computer and press F5 to run, there is a message 'unexpected MATLAB expression' what should I do?

Hello, during a calculation I got the following term: \varepsilon^{i_1 \ldots i_n}\varepsilon_{j_1 \ldots j_n} (a_{i_1}^{j_1}\ldots a_{i_n}^{j_n}) where \varepsilon is the levi-civita symbol and a_i^j are real numbers. Is it possible to simplify that expression?

in this photo there is the circuit and the KVL of the solution but when i tried to do the KVL i go from the arc(3 lines represents potential zero) in counter clockwise direction so i get V_L + V_C+V_R-V_s=0 when i go against the direction of a current the voltage is on PLUS when in the...

We have been doing research on the differential expression of one gene between two cell lines (A and B cell lines), with high expression in A cell line and no expression in B cell line. We found that ~250 bp in the promoter of the gene has its activity in A cell line, but no activity in B cell...

can anyone tell me how to get the real and imaginary parts of the following function : (x+ i y)* Log( a+i b) where x, y a and b are all real numbers and i =sqrt (-1). Thanks very much