1.

Find the sum of the following geometric progressions : 1,3,9,27,.... to 8 terms

Answer»

Common Ratio = r = \(\frac{3}{1}\) = 3

\(\therefore\) Sum of GP for n terms = \(\frac{a(r^n -1)}{r-1}\)..... (1)

⇒ a = 1, r = 3, n = 8

∴ Substituting the above values in (1) we get

⇒ \(\frac{1(3^8 -1)}{3-1}\)

⇒ \(\frac{3^8 -1}{2}\)

⇒ 3280



Discussion

No Comment Found