" 11."9(3)/(4)-:[2(1)/(6)+{4(1)/(3)-(1(1)/(2)+1(3)/(4))}

[4(1)/(5)-:{1(3)/(4)-(1)/(2)(3(1)/(2)-(1)/(4)-(1)/(6))}]

1(5)/(6)+[2(2)/(3)-{3(3)/(4)(3(4)/(5)-:9(1)/(2))}]

The sum of the infinite series (1)/(2) ((1)/(3) + (1)/(4)) - (1)/(4)((1)/(3^(2)) + (1)/(4^(2))) + (1)/(6) ((1)/(3^(3)) + (1)/(4^(3))) - ...is equal to

3+(x)/(4)=(1)/(2)(4-(x)/(3))-(5)/(6)+(1)/(3)(11-(x)/(2))

1+(1)/(2). (3)/(5) + (1.3)/(2.4) . (9)/(25)+(1.3.5)/(2.4.6).(27)/(125)+…...oo=