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Course: Class 10 Math (India) - Hindi > Unit 5

Lesson 4: Sum of first n terms of an AP
Math
Class 10 Math (India) - Hindi
Arithmetic progressions
Sum of first n terms of an AP
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Sum of n terms (intermediate)

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Problem

The sum of n terms of an arithmetic progression is given by:
Sn=72n2+172n
Find the fifth term, a5.
a5=
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi