The value of `sum_(r=0)^n(a+r+a r)(-a)^r` is equal to

Find the value of Sigma_(r=1)^(n) (a+r+ar)(-a)^r is equal to

Statement1: if n in Na n dn is not a multiple of 3 and (1+x+x^2)^n=sum_(r=0)^(2n)a_r x^r , then the value of sum_(r=0)^n(-1)^r a r^n C_r is zero Statement 2: The coefficient of x^n in the expansion of (1-x^3)^n is zero, if n=3k+1orn=3k+2.

The value of sum_(r=1)^n(-1)^(r+1)("^n C r)/(r+1) is equal to a. -1/(n+1) b. 1/n c. 1/(n+1) d. n/(n+1)

The value of sum_(r=0)^(50)(-1)^r((50)C_r)/(r+2) is equal to a . 1/(50xx51) b. 1/(52xx50) c. 1/(52xx51) d. none of these

The value of sum_(r=0)^(3n-1)(-1)^r 6nC_(2r+1)3^r is

The value of sum_(r=0)^(20)r(20-r) (.^(20) C_r)^2 is equal to a. 400^(39)C_(20) b. 400^(40)C_(19) c. 400^(39)C_(19) d. 400^(38)C_(20)

The value of sum_(r=1)^(11)tan^(2)((r pi)/(24)) is

The value of sum_(r=1)^n(sum_(p=0)^(r-1) ^nC_r ^rC_p 2^p) is equal to

The value of sum_(r=0)^(40) r""^(40)C_(r)""^(30)C_(r) is

If A=pi/5, then find the value of sum_(r=1)^8tan(r A)*tan((r+1)A)dot