If `1-1/3+1/5-1/7+1/9-1/(11)+=pi/4` , then value of `1/(1xx3)+1/(5xx7)+1/(9xx11)+` is `pi//8` b. `pi//6` c. `pi//4` d. `pi//36`

If 1-(1)/(3)+(1)/(5)-(1)/(7)+(1)/(9)-(1)/(11)+...=(pi)/(4), then value of (1)/(1xx3)+(1)/(5xx7)+(1)/(9xx11)+... is pi/8bpi/6c. pi/4d. pi/36

The value of sin^(-1)(cos((33pi)/5)) is (a) (3pi)/5 (b) -pi/(10) (c) pi/(10) (d) (7pi)/5

The value of sin^(-1)(cos(33pi)/5) is (a) (3pi)/5 (b) -pi/(10) (c) pi/(10) (d) (7pi)/5

The value of cos((2pi)/7)cos((4pi)/7)cos((6pi)/7) is a. -1//2 b. \ 1//2 c. \ 1//4 d. 1//8

The value of cos(2pi)/7cos(4pi)/7cos6/7pi is a. -1//2 b. \ 1//2 c. \ 1//4 d. 1//8

The value of sin^(-1)(cos(33pi)/5) is (3pi)/5 (b) pi/(10) (c) pi/(10) (d) (7pi)/5

The value of tan^(-1)(1)+cos^(-1)(-1/2)+sin^(-1)(-1/2) is equal to pi/4 b. (5pi)/(12) c. (3pi)/4 d. (13pi)/(12)

The value of sin^(-1)(-3/2)+cos^(-1)(cos\ (7pi)/6) is a. (5pi)/6 b. pi/2 c. (3pi)/2 d. none of these

The value of sin^(-1)(-sqrt3/2)+cos^(-1)(cos\ (7pi)/6) is a. (5pi)/6 b. pi/2 c. (3pi)/2 d. none of these

The value of (1+cos (pi)/(8))(1+cos (3 pi)/(8))(1+cos (5 pi)/(8))(1+cos (7 pi)/(8)) is