Q. Prove that 3 1 2 ×   3 1 4 × 3 1 8 . . . .   =   3
Q. Let x = 1+ a+a2 + .... and y = 1+b+b2+..., where |a|  <  1 and  |b| ​ <  1. Prove that

1 + a b + a 2 b 2   +   . . . .   =   x y x + y - 1

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Question 5

312×314×318×..=3312+14+18+....12+14+18+...12+122+123+...  is an infinite GP where a=12 and r=12sum of infinite GP=a1-r121-12=1212=1Hence 312+14+18+.... =31hence proved that 312+14+18+.... =3

Question 6
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