How do you integrate #int tan^2x#?

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# ?