What is int_1^(e^(pi/4)) 4/(x(1+(lnx)^2))dx∫eπ414x(1+(lnx)2)dx? Calculus Techniques of Integration Integration by Trigonometric Substitution 1 Answer maganbhai P. Mar 16, 2018 4tan^-1(pi/4)4tan−1(π4) Explanation: I=int_1^(e^(pi/4))4/(x(1+(lnx)^2))dxI=∫eπ414x(1+(lnx)2)dx Let, lnx=u=>1/x*dx=dulnx=u⇒1x⋅dx=du x=1=>u=ln1=>u=0andx=1⇒u=ln1⇒u=0and x=e^(pi/4)=>u=lne^(pi/4)=>u=pi/4x=eπ4⇒u=lneπ4⇒u=π4 :.I=int_0^(pi/4)4/(1+u^2)du=[4tan^-1u]_0^(pi/4) :.I=4[tan^-1(pi/4)-tan^-1(0)]=4[tan^-1(pi/4)-0] :.I=4tan^-1(pi/4) Answer link Related questions How do you find the integral int1/(x^2*sqrt(x^2-9))dx ? How do you find the integral intx^3/(sqrt(x^2+9))dx ? How do you find the integral intx^3*sqrt(9-x^2)dx ? How do you find the integral intx^3/(sqrt(16-x^2))dx ? How do you find the integral intsqrt(x^2-1)/xdx ? How do you find the integral intsqrt(x^2-9)/x^3dx ? How do you find the integral intx/(sqrt(x^2+x+1))dx ? How do you find the integral intdt/(sqrt(t^2-6t+13)) ? How do you find the integral intx*sqrt(1-x^4)dx ? How do you prove the integral formula intdx/(sqrt(x^2+a^2)) = ln(x+sqrt(x^2+a^2))+ C ? See all questions in Integration by Trigonometric Substitution Impact of this question 2074 views around the world You can reuse this answer Creative Commons License