Question

Binomial theorem ---- [2]

Answer 1

Last one , not getting the sollution

Answer 2

what exactly ar eyou not getting in that ?

Answer 3

(1+a)(1+b) = 1+a+b+ab
they have ignored ab term as the exponent becomes greater than 50

Answer 4

then in the first bracket, all exponents are even
hence after multiplication with terms like t^40, t^45...we would get t^80, t^90 ...which are way greater than t^50...and hence ignored.