In the end multiply by the derivative of 5t i.e., 5. Rest is fine except one typing error, for 1/2(tt)^-1/2 It should be 1/2(5t)^-1/2
The problem is: tansqrt(5t). I get that I need to use the chain rule but I think I'm messing it up.
So I did this: tansqrt(5t) = sec^2sqrt(5t) * 1/2(tt)^-1/2 = sec^2sqrt(5t)/2sqrt(5t).
However, this is the wrong answer. What am I missing?