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.