Manipal MET2010MathematicsBinomial Theorem
The number of terms in the expansion of ( 5 + [4] 11 )¹²⁴ which are integers, is equal to
Options
- A0
- B30
- C31
- D32
Correct answer
D. 32
Step-by-step solution
The general term in the expansion of ( 5 +4 11 )¹²⁴ is gathered T_ r+1 = ¹²⁴ C_r( 5 )^ 124-r ( [4] 11 )^r = ¹²⁴ C_r 5^ (124-r) / 2 11^ r / 4 gathered For integer terms r=0,4,8,12, , 124 Number of terms which are integers =32