the question is (y^2)/(25+y^2) dy.

here are my steps:

a=5

y=5tanx

dy=5secx^2 dx

[(5tanx)^2 * 5secx^2]/[25*(1+tanx^2)] dx

= [(5tanx)^2 * 5secx^2]/[25*secx^2] dx

=5tanx^2 dx

im stuck here.

I tried to use integration by parts to solve 5tanx^2 dx. but it didn't work out

The final answer should be y-5arctan(y/5)+C which c is any constant