Home
Class 12
MATHS
The value of underset(r=1)overset(18)sum...

The value of `underset(r=1)overset(18)sum cos^(2)(5r)^(@)`, where `x^(@)` denotes the x degree, is equal to

A

0

B

`7/2`

C

`(17)/2`

D

`(25)/2`

Text Solution

Verified by Experts

The correct Answer is:
C
Promotional Banner

Similar Questions

Explore conceptually related problems

The value of sum_(r=1)^(18) cos^(2)(5r)^(@) , where x^(@) denotes the x degree, is equal to

underset(r=1)overset(n)sum ( r )/(r^(4)+r^(2)+1) is equal to

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____.

underset(r=1)overset(n)(sum)r(.^(n)C_(r)-.^(n)C_(r-1)) is equal to

If underset(r=1)overset(n)sum [log_(2) r]=2010 where [.] denotes greatest integer function, then the sum of the digits of n is:

The value of sum_(r=1)^(5)(x^(r)+(1)/(x^(r)))^(2), where x^(2)+x+1=0is:-

The limit of the series underset(r=1)overset(n)sum (r)/(1+r^(2)+r^(4)) as n approaches infinity, is

If underset(r=1)overset(10)sum r! (r^(3)+6r^(2)+2r+5)=alpha (11!) , then the value of alpha is equal to .......