Why Is My Calculation of the Antiderivative for sqrt(20-x) Incorrect?

[hekoshi]

I can't seem to get this antiderivitive correct: sqrt(20-x) from 0 to 20.

I end up with -(2/3)(sqrt(20-x)^(3/2) which is zero evaluated at either of the two limits.

This is not correct since the area below the curve of the original equation is definitely not 0.

 

[Mark44]

You shouldn't have sqrt in your answer since that's already accounted for in the 3/2 exponent. Also, the antiderivative functionis not zero for x = 0. Check it again.

 

[epenguin]

Yes and also it is not zero at both the limits; it should work out now.

 

[hekoshi]

oops, i meant to write -(2/3)(20-x)^(3/2), but yeah, i didn't evaluate it correctly the first time. It should be:

F(b)-F(a)=-(2/3)(20-20)^(3/2)-(-(2/3)(20-0)^(3/2))

*Facepalm* I blame it on lack of sleep, haha.

thanks.