# Math Help - A few questions about integrals

1. ## A few questions about integrals

Hello!

I am having problem solving this one:

∫ -y/(x^2+y^2)dx
∫t* sqrt(1+4t^2) dt

Finding g(x) in the following equation:

(g'(x)-g(x))x sin xy = 0

2. Originally Posted by tinyone
Hello!

I am having problem solving this one:

∫ -y/(x^2+y^2)dx
Think of trigonometric functions. You'll have to use Inverse tangent function here..

Originally Posted by tinyone
∫t* sqrt(1+4t^2) dt
Use the substitution rule.. let $u=4t^2+1$

show your work if you are having any problems.