nth term of a G.P = apn-1
1st term of G.P = a = 6
2nd term of G.P = ar = 6r
3rd term G.P = ar2 = 6r2
nth term of an A.P
= a + (n - 1)d
1st term of A.P = a
4th term of A.P = a + 3d
10th term of A.P = a + 9d
The 1st three terms of G.P are
a, a + 3d, a + 9d
= $\frac{a}{a + 3d}$ = $\frac{a\; +\; 3d}{a\; + \;9d}$
a2 + 9ad = a2 + 6ad + 9d2
3ad = 9d2
3a = 9d; a = 3d
But a = 6
therefore $\frac{3d}{3}$; d = 2
johnmulu answered the question on March 6, 2017 at 13:51
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