Answers>Maths>IB>Article

The sixth term of an arithmetic sequence is 8 and the sum of the first 15 terms is 60. Find the common difference and list the first three terms.

Formulae to be used: nth term of an arithmetic sequence un= u1 + (n-1)d and sum of the first n terms of an arithmetic series Sn = (n/2) * (2u1 + (n-1)d) Substitute known values: u1 + 5d = 8(15/2) * (2u1 + 14d) = 60 Attempt to solve simultaneous equations, by eliminating u1 and d, in turn, to get d = -2, and u1 = 18, u2 = 16, u3 = 14.

BC
Answered by Bence C. Maths tutor

1447 Views

See similar Maths IB tutors

Related Maths IB answers

All answers ▸

Find an antiderivative to the function f(x) = e^x cos(x)


How should I approach a proof by induction question?


Find a and b (both real) when (a+b*i)^2=i.


f(x)=sin(2x) for 0<x<pi, find the values of x for which f is a decreasing function


We're here to help

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

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences