A friend and I were doing some math together when we had to integrate 2(100 + t).
I just multiplied it out and integrated 200 + 2t, which should be 200t + t^2.
He did u-substitution and got (100 + t)^2
When I take the derivative of both of ours, I seem to get the same thing. But (100 + t)^2 = 10,000 + 200t + t^2, which is not equal to just 200t + t^2.
What is going on here?