Find n if the coefficients of 4th the 13th terms in the expansion of `(a+b)^n` are equal.

If the coefficient of 4th term in the expansion of (a+b)^n is 56, then n is

If the coefficient of 4th term in the expansion of (a+b)^n is 56, then n is

If the coefficients of (2r + 4)th, (r - 2)th terms in the expansion of (1 + x)^18 are equal, find r.

If the coefficients of (p+1) th and (P+3) th terms in the expansion of (1+x)^(2n) are equal then prove that n=p+1

(2) If the coefficients of (2r + 4)th, (r - 2)th terms in the expansion of (1 + x)^18 are equal, find r.

Find a if 17th and 18th terms in the expansion of (2+a)^(50) are equal.

Find a if 17th and 18th terms in the expansion of (2+a)^(50) are equal.

Find a if 17th and 18th terms in the expansion of (2+a)^(50) are equal.

If the coefficient of (2r+4)th and (r-2)th terms in the expansion of (1+x)^(18) are equal, find r .

Given positive integers r>1,n> 2, n being even and the coefficient of (3r)th term and (r+ 2)th term in the expansion of (1 +x)^(2n) are equal; find r