How do you evaluate int x/sqrt(1-x^2) from [-1/2, 0]?

1 Answer
Dec 13, 2016

The answer is =(sqrt3-2)/2=-0.134

Explanation:

We do the integration by substitution

intx^ndx=x^(n+1)/(n+1)+C (n!=-1)

Let u=1-x^2, =>, du=-2xdx

int(xdx)/sqrt(1-x^2)=-1/2int(du)/sqrtu

=-1/2intu^(-1/2)du=-1/2u^(1/2)/(1/2)

=-sqrt(1-x^2)

So,

int_(-1/2)^0(xdx)/sqrt(1-x^2)=[-sqrt(1-x^2)]_(-1/2)^0

=-1+sqrt(1-1/4)=-1+(sqrt3/2)

=(sqrt3-2)/2=-0.134