[" value of "a" ."],[" Find the coefficient of "x^(4)" in the expansion of "(1+x)^(n)(1-x)^(n)" .Deduce that "],[C_(2)=C_(0)C_(4)-C_(1)C_(3)+C_(2)C_(2)-C_(3)C_(1)+C_(4)C_(0)" ,where "C_(r)" stands for "^(n)C_(r)]

Find the coefficient of x^4 in the expansion of (1+x)^n (1-x)^n . Deduce that C_2=C_0C_4-C_1C_3+C_2C_2-C_3C_1+ C_4 C_0 .

Find the coefficient of x^(n-r) in the expansion of (x+1)^n (1+x)^n . Deduce that C_0C_r+C_1C_(r-1)+......+C_(n-r) C_n= ((2n!))/((n+r)!(n-r)!) .

The coefficient of x^(4) in the expansion of (1+x+x^(2)+x^(3))^(n) is *^(n)C_(4)+^(n)C_(2)+^(n)C_(1)xx^(n)C_(2)

If C_(n) is the coefficient of x^(n) in the expansion of (1+x)^(n) then C_(1)+2. C_(2)+3. C_(3)+..+n. C_(n)

Prove that C_(0)2^(2)C_(1)+3C_(2)4^(2)C_(3)+...+(-1)^(n)(n+1)^(2)C_(n)=0 where C_(r)=nC_(r)

If C_(0) , C_(1), C_(2), …, C_(n) are the binomial coefficients in the expansion of (1 + x)^(n) , prove that (C_(0) + 2C_(1) + C_(2) )(C_(1) + 2C_(2) + C_(3))…(C_(n-1) + 2C_(n) + C_(n+1)) ((n-2)^(n))/((n+1)!) prod _(r=1)^(n) (C_(r-1) + C_(r)) .

If C_(0) , C_(1), C_(2), …, C_(n) are the binomial coefficients in the expansion of (1 + x)^(n) , prove that (C_(0) + 2C_(1) + C_(2) )(C_(1) + 2C_(2) + C_(3))…(C_(n-1) + 2C_(n) + C_(n+1)) ((n-2)^(n))/((n+1)!) prod _(r=1)^(n) (C_(r-1) + C_(r)) .

If C_(0), C_(1) C_(2) ….., denote the binomial coefficients in the expansion of (1 + x)^(n) , then (C_(0))/(2) - (C_(1))/(3) + (C_(2))/(4)- (C_(3))/(5)+...+ (-1)^(n)(C_(n))/(n+2) =

If C_(0), C_(1) C_(2) ….., denote the binomial coefficients in the expansion of (1 + x)^(n) , then (C_(0))/(2) - (C_(1))/(3) + (C_(2))/(4)- (C_(3))/(5)+...+ (-1)^(n)(C_(n))/(n+2) =