Recent content by fiziksfun

can someone please show me why sinxcos2x = (sin3x - sinx)*0.5 I've been working on it for thirty minutes

My professor said the Fourier series of sinx*cosx is simply 0.5sin2x. Is this right?? Is there no summation?? I don't understand why .. Help!

Homework Statement I was just wondering if there is a formula for the product rule when you take two derivatives ... ? Homework Equations I know the product rule for one derivative .. is u'v + uv' ! The Attempt at a Solution I just want a formula without a proof

Homework Statement how do i integrate v^2 / v^2 + 4 Homework Equations i understand this has something to do with arctan but if i use u substitution to let v=(u/2) so (on the bottom) it becomes (1/4)(1+(v/2)^2) there's still a v^2 on the top which the u substitution does not...

Homework Statement is e^-ln(x) the same as 1/x ?? Homework Equations The Attempt at a Solution

Homework Statement 1/y = kr + C/e^(rt) Is this equal to y = 1/kr + e^(rt)/C Thanks Homework Equations The Attempt at a Solution

Homework Statement We have y' = y^(1/3) with initial condition y(0)=0 It's stated that the partial derivative ∂f/∂y does not exist at y=0. Can anyone explain to me why this is? I don't understand how you can take the partial derivative if its not in the form f(x, y); there...

i don't understand how the chain rule applies in this situation! help! how do i take the derivative of (v-4)/(1-v) with respect to x?? there is no x!

Homework Statement i have the equation dy/dx = \frac{(y/x)-4}{1-(y/x)} i am told that v(x)=xy and v=y/x Express this using v, dv/dx, and xI can get dy/dx = \frac{(v)-4}{1-(v)} but that's it Homework Equations ?? The Attempt at a Solution I don't even know how to do dv/dx can anyone...

Is work done if the total displacement is 0? It doesn't matter what path the object took to get from A back to A, right? As long as it ends at A, then its zero work, correct? So work IS NOT path dependent, it's a state function, like energy, right ?

Homework Statement show that the plane 2x - y + 4z = 81 never intersects the line \frac{x-2}{3}=\frac{y-3}{2}=z-1 Homework Equations ?? The Attempt at a Solution I wanted to show that the line and the plane were parallel. So the unit vector for the line would be...

What is the bond order of CO+ I don't even understand how do this because C does not obey the octet rule in this case. Can anyone help?

If a power series, \sumc(subk)*x^{k} diverges at x=-2, then it diverges at x=-3. True or False? I said true, but was confused by my reasoning. Does anyone have any suggestions?

Is the limit 1?

Does it diverge because the lim as k approaches infinity is 2/3 ?