How do you find the integral of int 1/(sqrt(x)*(1+x)) dx1x(1+x)dx?

1 Answer
Jul 9, 2018

int1/(sqrtx(1+x))dx=2arc tan(sqrtx)+c1x(1+x)dx=2arctan(x)+c

Explanation:

We know that,

color(red)((1)d/(dx)(arc tanx)=1/(1+x^2)=>int1/(1+x^2)dx=arc tanx+c(1)ddx(arctanx)=11+x211+x2dx=arctanx+c

We have ,

I=int1/(sqrtx(1+x))dxI=1x(1+x)dx

Subst. color(blue)(sqrtx=u=>x=u^2=>dx=2udux=ux=u2dx=2udu

So ,

I=int1/(u(1+u^2))2u*duI=1u(1+u2)2udu

=2int1/(1+u^2)du...tocolor(red)(Apply(1)

=2arc tan u+c

Subst. back color(blue)(u=sqrtx ,we get

I=2arc tan(sqrtx)+c