What is the integration of int((x(tanx)^-1)dx)/(1+x^2)^(3/2)(x(tanx)1)dx(1+x2)32 ?

int((x(tanx)^-1)dx)/(1+x^2)^(3/2)(x(tanx)1)dx(1+x2)32

1 Answer
Jul 30, 2018

int((x(tanx)^-1)dx)/(1+x^2)^(3/2)=-(tan^-1x)(1/sqrt(1+x^2))+x/sqrt(1+x^2)+C(x(tanx)1)dx(1+x2)32=(tan1x)(11+x2)+x1+x2+C

Explanation:

int((x(tanx)^-1)dx)/(1+x^2)^(3/2)(x(tanx)1)dx(1+x2)32

Put x=tanzx=tanz

dx=sec^2zdx=sec2z

int (tanz.z.(sec^2z))/((sec^2z)^(3/2)).dztanz.z.(sec2z)(sec2z)32.dz

int(tanz.z.dz)/secz.dztanz.z.dzsecz.dz

int(sinz/cosz).cosz.z.dz(sinzcosz).cosz.z.dz

intsinz.z.dzsinz.z.dz

Now I'm gonna use integration by parts

intu.dv = u.v -intdu.vu.dv=u.vdu.v

u = z dz u=zdz
du = 1du=1

dv=sinzdv=sinz
v=-coszv=cosz

Now put values in formula

intz.sinz.dz=z(-cosz)-int(-cosz)z.sinz.dz=z(cosz)(cosz)

intz.sinz.dz=z(-cosz)+intcoszz.sinz.dz=z(cosz)+cosz

intz.sinz.dz=z(-cosz)+sinz +Cz.sinz.dz=z(cosz)+sinz+C.......(1)

As we know cosz=1/seczcosz=1secz

secz=sqrt(1+tan^2z)secz=1+tan2z

And is equal to tanz =xtanz=x above.

then, secz=sqrt(1+x^2)secz=1+x2

cosz=1/sqrt(1+x^2)cosz=11+x2

sinz=sqrt(1-cos^2z)sinz=1cos2z

sinz=sqrt(1-1/(1+x^2))sinz=111+x2

sinz=sqrt(x^2/(1+x^2))sinz=x21+x2

sinz = x/sqrt(1+x^2)sinz=x1+x2

Now put value of z, cosz, sinz in eq 1

Here is Final answerint((x(tanx)^-1)dx)/(1+x^2)^(3/2)=tan^-1x(-1/sqrt(1+x^2))+x/sqrt(1+x^2) +C(x(tanx)1)dx(1+x2)32=tan1x(11+x2)+x1+x2+C