How do you find the indefinite integral of #int 4/(1+t^2)dt#? Calculus Introduction to Integration Integrals of Polynomial functions 1 Answer Andrea S. Jan 9, 2017 #int 4/(1+t^2)dt =4arctant+C# Explanation: Substitute: #t=tanx# #dt = (dx)/(cos^2x)# #x=arctan t# So: #int 4/(1+t^2)dt = 4 int 1/(1+tan^2x) (dx)/(cos^2x)=4 int 1/(1+sin^2x/cos^2x) (dx)/(cos^2x)=4 int (dx)/(cos^2x+sin^2x) =4 int dx = 4x+C = 4arctant+C# Answer link Related questions How do you evaluate the integral #intx^3+4x^2+5 dx#? How do you evaluate the integral #int(1+x)^2 dx#? How do you evaluate the integral #int8x+3 dx#? How do you evaluate the integral #intx^10-6x^5+2x^3 dx#? What is the integral of a constant? What is the antiderivative of the distance function? What is the integral of #|x|#? What is the integral of #3x#? What is the integral of #4x^3#? What is the integral of #sqrt(1-x^2)#? See all questions in Integrals of Polynomial functions Impact of this question 5141 views around the world You can reuse this answer Creative Commons License