Question

6
1)
If S, = 1023 , r = 4, Find a​

Answer 1

Answer:

a=3

Step-by-step explanation:

Given'

summatin of first 5 G.P series, S5=1023

and common ratio, r=4

summation of G.P terms having n number of terms =\frac{a\times(r^n -1)}{r-1}r−1a×(rn−1)

hence, summation of first five terms = \frac{a\times(r^5 -1)}{r-1}r−1a×(r5−1)

                                                   1023  = \frac{a\times(4^5 -1)}{4-1}4−1a×(45−1)

                                                      a=\frac{1023\times 3}{4^5 -1}45−11023×3

                                                       a=3