Find the value of ` ""^(47)C_4+ underset (r=1) overset( 5) sum ""^(52-r)C_3`

The value of ""^(50)C_4 + underset(r=1) overset(6)sum ""^(56-r)C_3 is

If .^(47)C_(4)+underset(r=1)overset(5)(sum).^(52-r)C_(3) is equal to

Find the value of underset(r = 0) overset(oo)sum tan^(-1) ((1)/(1 + r + r^(2)))

Find the value of underset(r = 1)overset(10)sum underset(s = 1)overset(10)sum tan^(-1) ((r)/(s))

What is .^(47)C_(4)+.^(51)C_(3)+ underset(j=2)overset(5)sum.^(52-j)C_(3) equal to ?

If S_(n) = underset (r=0) overset( n) sum (1) /(""^(n) C_(r)) and T_(n) = underset(r=0) overset(n) sum (r )/(""^(n) C_(r)) then (t_(n))/(s_(n)) = ?

Find underset(r=0) overset(10)sumr^ (10)C_(r).3^(r).(-2)^(10-r)

Find the value of :^50C_4+sum_(r=1)^6 .^(56-r)C_3.

The value of underset(r=0)overset(40)sumr.^(40)C_(r).^(30)C_(r) is

let underset(r=0)overset(2010)(sum)a_(r)x^(r)=(1+x+x^(2)+x^(3)+x^(4)+x^(5))^(402) and underset(r=0)overset(2010)(sum)a_(r)=a, then the value of ((underset(r=0)overset(2010)(sum)r.a_(r))/(underset(r=0)overset(2010)(sum)a_(r))) is equal to____.