Find 1 + (xy) + (xy)2 + (xy)3 + …… if a= 1+ 2x + 3x2 + 4x3+….. ( -1<a<1) and b= 1+3y + 6y2 + 10y3+…. (-1<b<1)
Option (a)
Assume x=0 and y=0. Then the equation gives a value of 1. Put the values of x
and y to get a and b. a=1 and b=1
Go from answer options. Only answer option a gives 1