Question

The number of terms which are free from fractional powers in the expansion of (a1/5 + b2/3)45a ≠ b is

Solution

Correct option is

4

The general term in the expansion of (a1/5 + b2/3)45 is

         

This will be from fractional powers if both r/5 and 2r/3 are whole numberi.e. if r = 0, 15, 30, 45. Hence, there are only four terms which are fee from fractional powers.

SIMILAR QUESTIONS

Q1

Find the 11th in the expression of 

Q2

Find the term independent of x in 

Q3

Show that 11n+2 + 122n+1 is divisible by 133.

Q4

Evaluate C1 – 2. C2 + 3. C3 – 4. C4 +….+ (– 1)n+1n. Cn 

Q5

The digit at unit place in the number 171995 + 111995 – 71995 is

Q6

If the sum of the coefficients in the expression of (1 + 2x)n is 6561. The greatest term in the expression at x = 1/2 is

Q7

The number of terms in the expression of (a + b + c)n, where n Ïµ N, is

Q8

If n is an odd natural, then  equals

Q9
Q10

The coefficient of xm in (1 + x)r + (1 + x)r+1 + (1 + x)r+2 +….+ (1 + x)nr≤ m ≤ n is