.
Find the sum of the first 30 terms of an arithmetic series if the 1st term is 5 and the 30th term is 100.
~~~~~~~~~~~~~~~~~~~~~~
Use the formula for the sum of the first n terms of an AP in the form
= = = (5+100)*15 = 105*15 = 1575. ANSWER
Solved.
-----------------------
For introductory lessons on arithmetic progressions see
- Arithmetic progressions
- The proofs of the formulas for arithmetic progressions
- Problems on arithmetic progressions
- Word problems on arithmetic progressions
in this site.