Homework Statement [/B]
J(a, b, c;y)=∫aydx/√((x-a)(x-b)(x-c)), let a<b<cHomework Equations
f(θ, k)=∫0θdx/√(1-k2sin2(x)), k≤1
The Attempt at a Solution
This is an example from my study material, and I don't understand the first step they do.
Let x=a+(b-a)t, dx=(b-a)dt
Wait...what? Why? How...