The question reads
Find the surface area generated by rotating x=e^t -t & y=4e^t for 0 to 1 (this is in terms of t) about the y axis.
So i've managed to get the integral as far as
i'm just not sure what to do after that i thought about multiplying out the square root but even if i were to do that i can't think of a proper u-sub that could work. So what do you think am i on the right track or is there an easier way that i'm just not seeing.
for this problem i'm supposed to be using the integral of x(t) times ds where
ds=((dx/dt)^2 + (dy/dt)^2)^(1/2)
After i did this i got (e^(2t)+1)^(1/2).....
...And now i just realized where i went wrong, i forgot to square the two resulting in something zeroing out where it shouldn't have. oh well thanks for your help anyway.