Integrate x^2e^x with respect to x between the limits of x=5 and x=0.

This question is to test integration by parts.  First let u=x2 and u'=2x as a result, and v'=ex and so v=ex too. Then use the by parts formula to express the integral as x2ex​​​​​​​-2(integral of):(xex​​​​​​​-ex​​​​​​​)dx. Using the by parts method again with the integral we just found we can reduce the second expression to x2ex​​​​​​​-2xex​​​​​​​+2ex​​​​​​​. This is the indefinite integration result of the expression in question, (without the +c!) and the question is finished by first plugging 5 into the answer, to get 25e5-10e5​+2e5​ and then plugging in 0, to give just 2. Subtracting the lower limit from the upper limit results gives 25e5​-10e5​+2e5​-2, which is a constant term and is the answer to the question (in physical terms it is the area underneath the curve y=x2ex between the points x=0 and x=5)

Answered by Alex A. Maths tutor

4545 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Find the equation of the tangent to the curve y = (5x+4)/(3x -8) at the point (2, -7)


Solving Quadratic Equations


Consider a cone of vertical height H (in metres) and base radius R (in metres) which is full with water. The cone, at time t=0, starts to leak such that it loses water at a rate of k m^3 per second. Give an expression for the rate of change of H.


Find the derivative of f(x)=x^2log(2x)


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2024

Terms & Conditions|Privacy Policy