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
Sum of the coefficients in the expression of (1 + 2x)n = 6561
⇒ (1 + 2x)n = 6561, when x = 1
⇒ 3n = 6561
⇒ 3n = 38 ⇒ n = 8
Hence, 5th term is the greatest term.
Find the 11th in the expression of
Find the term independent of x in
Show that 11n+2 + 122n+1 is divisible by 133.
Evaluate C1 – 2. C2 + 3. C3 – 4. C4 +….+ (– 1)n+1n. Cn
The digit at unit place in the number 171995 + 111995 – 71995 is
The number of terms in the expression of (a + b + c)n, where n Ïµ N, is
The number of terms which are free from fractional powers in the expansion of (a1/5 + b2/3)45, a ≠ b is
If n is an odd natural, then equals
The coefficient of xm in (1 + x)r + (1 + x)r+1 + (1 + x)r+2 +….+ (1 + x)n. r≤ m ≤ n is