Home of real teaching & learning
  • Full support for teachers
  • Focus on critical thinking
  • Engaging classroom activities
  • Integrated student eBook
  • Assessed tasks / qBank
  • Practice exam questions
Find out more Download brochure

The InThinking Guarantee: Our sites are written by expert practitioners and not by AI

See our AI policy

Disclaimer: InThinking subject sites are neither endorsed by nor connected with the International Baccalaureate Organisation.

Don't miss out, find out!

P.o.t.W. #36 Solution

Let {u_1} be the first term and d be the common difference of the arithmetic series. 2500d = 2500\;\;\;\; \Rightarrow \;\;\;\;d = 1 Then the sum of the first fifty terms, {S_{50}} , is \displaystyle{S_{50}}=\frac{{50}}{2}\left[{2{u_1} + \left( {50 - 1} \right)d}\right] = 50{u_1} + 1225d = 200 The sum of the first one hundred terms, {S_{100}} , is...

Help