JEE Main 2019 Mathematics question
The total number of irrational terms in the binomial expansion of is:
Answer: (A)
Solution
Rational terms need r ≡ 0 (mod 10): r = 0, 10, …, 60 (7 terms); 61 − 7 = 54.
The total number of irrational terms in the binomial expansion of is:
Rational terms need r ≡ 0 (mod 10): r = 0, 10, …, 60 (7 terms); 61 − 7 = 54.