1.

How many terms of the G.P. 1,4,16 ..... must be taken to have their sum equal.

Answer»

Sn = 3 + 32 +33 +..... = \(\frac{3(3^n-1)}{3-1}=\frac32(3^n-1)\) 

S'n= 1 + 7 + 16 + ..

 = 40 + 41 + 42+.....

 = \(\frac{4^0(h^n-1)}{4-1}\) = \(\frac{4^n-1}3\)



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