The value of `sum_(r=0)^(10)cos^3((rpi)/3)` is equal to (a)`1/4` (b) `1/8` (c) `-1/4` (d) `-1/8`

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

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)

("lim")_(n->oo)sum_(x=1)^(20)cos^(2n)(x-10) is equal to (a) 0 (b) 1 (c) 19 (d) 20

The value of ""^(50)C_(4)+sum_(r=1)^(6)""^(56-r)C_(3) is

The value of (1+cospi/8)(1+cos(3pi)/8)(1+cos(5pi)/8)(1+cos(7pi)/8)i s (a)1/4 (b) 3/4 (c) 1/8 (d) 3/8

The value of sin^3 10^0+sin^3 50^0-sin^3 70^0 is equal to (a) -3/2 (b) 3/4 (c) -3/4 (d) -3/8

The value of cos^(-1)sqrt(2/3)-cos^(-1)((sqrt(6)+1)/(2sqrt(3))) is equal to (A) pi/3 (B) pi/4 (C) pi/2 (D) pi/6

The value of cos^2 10^0-cos10^0cos50^0+cos^2 50^0 is equal to 4/3 (b) 1/3 (c) 3/4 (d) 3

The value of sum_(r=0)^(10) (-1)^(r).4^(10-r)""^(30)C_(r)""^(30-r)C_(10-r) is equal to

The value of ("lim")_(nvecoo)sum_(r=1)^(4n)(sqrt(n))/(sqrt(r)(3sqrt(r)+sqrt(n))^2) is equal to 1/(35) (b) 1/4 (c) 1/(10) (d) 1/5