Smart people of VGChartz, help me with my maths (again).

[scottie]

I shant do your maths for you. The point of homework is to learn, not to get the right answers.

That said, I can try to help you to learn :)

iii is best solved by using an integrating factor
http://en.wikipedia.org/wiki/Integrating_factor

The basic steps should be
1 Put the equation in the form
dy/dt + p(t)y = g(t)

2 multiply each of these terms by an as yet unknown term u(t)

3 Write out a value for u(t) that is recognised as the derivative of a fairly simple expression
(you will need the identity that
d [u(t)y] / dt = u(t) dy/dt + du(t)/dt y

By using that, I determined that
du(t)/dt = -t^2 . u(t)

4 rearrange this to get all the u(t) terms on one side, and use standard integrals to determine u(t) (you should get a multiplicative constant, just let it equal 1)

5 Plug your value for u(t) back into the first equation that used u(t)

6 integrate both these sides, remembering to put a constant of integration +c on the right hand side

7 rearrange to get y on its own

My answer was y = e^((t^3)/3)

I shall have a look at the others, and if you get stuck give me a yell