If `(1-x)^(-n)=a_0+a_1x+a_2x^2++a_r x^r+ ,t h e na_0+a_1+a_2++a_r` is equal to `(n(n+1)(n+2)(n+r))/(r !)` `((n+1)(n+2)(n+r))/(r !)` `(n(n+1)(n+2)(n+r-1))/(r !)` none of these

If (1-x)^(-n)=a_0+a_1x+a_2x^2++a_r x^r+ ,t h e na_0+a_1+a_2++a_r is equal to a. (n(n+1)(n+2)(n+r))/(r !) b. ((n+1)(n+2)(n+r))/(r !) c. (n(n+1)(n+2)(n+r-1))/(r !) d. none of these

If (1-x)^(-n)=a_0+a_1x+a_2x^2++a_r x^r+ ,t h e na_0+a_1+a_2++a_r is equal to (a) (n(n+1)(n+2)(n+r))/(r !) (b) ((n+1)(n+2)(n+r))/(r !) (c) (n(n+1)(n+2)(n+r-1))/(r !) (d)none of these

If (1-x)^(-n)=a_(0)+a_(1)x+a_(2)x^(2)+...+a_(r)x^(r)+..., then a_(0)+a_(1)+a_(2)+...+a_(r) is equal to (n(n+1)(n+2)...(n+r))/(r!)((n+1)(n+2)...(n+r))/(r!)(n(n+1)(n+2)...(n+r-1))/(r!) none of these

If (1+x)^n=a_0+a_1x+a_2x^2+....+a_nx^n , then (a_0-a_2+.....)^2+(a_1-a_3+.....)^2 is equal to (A) 3^n (B) 2^n (C) ((1-2^n)/(1+2^n)) (D) none of these

If (1-x^2)^n=sum_(r=0)^na_rx^r(1-x)^(2n-r) , then a_r is equal to

If (1-x^(2))^(n)=sum_(r=0)^(n)a_(r)x^(r)(1-x)^(2n-r), then a_(r) is equal to ^(n)C_(r) b.^(n)C_(r)3^(r) c.^(2n)C_(r) d.^(n)C_(r)2^(r)

If (1-x^2)^n=sum_(r=0)^n a_r x^r(1-x)^(2n-r),t h e na_r is equal to a.) ^n C_r b.) ^nC_r3^r c.) ^2n C_r d.) ^nC_r2^r

If Sigma_(r=1)^(2n) sin^(-1) x^(r )=n pi, then Sigma__(r=1)^(2n) x_(r ) is equal to

If Sigma_(r=1)^(2n) sin^(-1) x^(r )=n pi, then Sigma__(r=1)^(2n) x_(r ) is equal to

If (1-x^2)^n=sum_(r=0)^n a_r x^r(1-x)^(2n-r),t h e na_r is equal to ^n C_r b. ^n C_r3^r c. ^2n C_r d. ^n C_r2^r