Find INT{2,1}{x^4 + 3x^2 + 2}

This is a typical AS-level Maths question.

  1. We see it’s a definite integral so start by drawing some big square brackets with the “limits” (2 and 1).

  2. We go through the expression inside the integral (the “integrand”) term by term and integrate each one. To integrate, we raise the power by one and divide by the new power. E.g. “x to the 4” would become “ one fifth x to the five” [would use whiteboard here]

  3. Remember, this is a definite integral so we don’t need to add ‘C’ at the end!

  4. We now substitute x = 2 into our integrated expression (just go through and replace x’s with 2’s - don’t change anything else yet). Then we substitute x = 1 into the expression and subtract it from what we just worked out. [again, on whiteboard]

  5. To make life easier, we keep the fractions as fractions and whole numbers as whole numbers until the end. We expand out the brackets carefully and, finally, combine everything into one number to get our final answer.

  6. [As an extra] what we just worked out is the area underneath the “integrand” curve between x = 1 and x = 2.

Answered by Andrew F. Maths tutor

3493 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Find the two real roots of the equation x^4 -5=4x^2 Give the roots in an exact form.


Solve 4x/(x+1) - 3/(2x+1) = 1


Calculate the indefinite integral of xsinx


Susan is researching the population growth of a city. She proposes that x, the number of people in the city, t years after 2017 is given by x=250,000e^(0.012t) A.population in 2017 B.population in 2020 C.During which year would the population have doubled


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 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences