A sequence is defined as: U(n+1) = 1/U(n) where U(1)=2/3. Find the sum from r=(1-100) for U(r)

Un+1=1/Un where U1= 2/3First of all, we need to find U2 and U3 and so on, up until we notice a pattern in the answers. U2 = 1/(2/3) = 3/2U3 = 1/(3/2) = 2/3As we can see, U1 and U3 are equal, and so we know that for every 'n' that is odd, Un will equal 2/3. This is similar for ever 'n' that even where Un will equal 3/2.Therefore in total for this summation, there will be 50 lots of '2/3' and 50 lots of '3/2' so the answer will be 50(2/3) + 50(3/2) = 325/3

Answered by Maths tutor

5113 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Two particles, A and B, are moving directly towards each other on a straight line with speeds of 6 m/s and 8 m/s respectively. The mass of A is 3 kg, and the mass of B is 2 kg. They collide to form a single particle of speed "v" m/s. Find v.


If n is an integer prove (n+3)^(2)-n^(2) is never even.


Differentiate the function: y = sin(x^2)*ln(5x)


f(x) = x^3 - 13x^2 + 55x - 75 , find the gradient of the tangent at x=3


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