ok so basically we are doing lengths and planes of curves.. i m lost to how the solution manual gets this..
the get:
f '(x) = x (x^2 + 2)^ 1/2
= integral ( 0 to 3) x (x^2 + 2)^ 1/2
im ok till here
int ( 0 to 3) x (1 + {x^2 + 2} x^2)^ 1/2
---------------^---------------^
my question is where did that +1 and x^2 come from how do tthey know they go there?? for other problems how would i know to get those correct values ??