Evaluate the indefinite integral: ∫ (e^x)sin(x) dx

Note: for what’s about to come, ' denotes derivative with respect to x. Method 1 (integration by parts): let I = (e^x)sin(x) dx let u = sin(x), u' = cos(x) and v' = e^x = v then integrate by parts, => I = uv - ∫u’v dx, substitute in u,v and u’ obtains: I =(e^x)sin(x) - ∫ (e^x)cos(x) dx () Now integrate by parts ∫ (e^x)cos(x) dx: let a = cos(x), a' = -sin(x) and b' = b = e^x hence: ∫ (e^x)cos(x) dx =(e^x)cos(x) + I, substitute into (): I = (e^x)(sin(x) + cos(x)) - I + C, for some constant C => I = 1/2(e^x)(sin(x) + cos(x)) + C  Method 2 (compare coefficients): Let y = (e^x)(Acos(x) + Bsin(x)), for some constants A, B to be determined => y' =(e^x)((A+B)cos(x) + (B-A)sin(x)) ≡(e^x)sin(x), hence by comparing coefficients, we have: B - A = 1 and A + B = 0 => B = 1/2, A = -1/2 => y = (1/2)(e^x)(sin(x) + cos(x)) + D, for some constants D

SN
Answered by ShenZhen N. Maths tutor

12670 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

AS Maths ->Expresss x^2 + 3x + 2 in the form (x+p)^2 + q... where p and q are rational number


Describe the set of transformations that will transformthe curve y=x^ to the curve y=x^2 + 4x - 1


integrate (2x)/(x^2+1) dx with limits 1, 0


A stone is thrown from a bridge 10m above water at 30ms^-1 30 degrees above the horizontal. How long does the stone take to strike the water? What is its horizontal displacement at this time?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning