If `alpha + beta = 90^0`, show that the maximum value of `cos alpha.cos beta` is `1/2`.

If alpha+beta=90^@ , show that the maximum value of cos alpha cos beta is (1)/(2)

If alpha+beta=90^(0) ,then the minimum and maximum values of cos alpha*cos beta are (A) -1/3 and 1/3 (B) -1 and 1 (C) -1/4 and 1/4 (D) -1/2 and 1/2

If cos alpha + cos beta = 0 = sin alpha + sin beta, then value of cos 2 alpha + cos 2 beta is

If alpha+beta=90^@ , and alpha=2 beta , then the value of 3 cos^2 alpha-2 sin^2 beta is: यदि alpha+beta=90^@ , और alpha=2 beta , तो 3 cos^2 alpha-2 sin^2 beta का मान ज्ञात करें:

Let cos alpha + cos beta =2 and sinalpha + sinbeta =0 , where 0 le alpha le 90^(@), 0 le beta le 90^(@) . What is the value of cos2alpha - cos 2beta ?

If alpha+beta=90^@ and alpha=2beta , then the value of 3cos^2alpha-2sin^2beta is equal to:

if alpha and beta satisfy sin alpha cos beta=-(1)/(2), then the greatest value of 2cos alpha sin beta is

If alpha and beta satisfy sin alpha cos beta=-((1)/(2)), then the greatest value of 2cos alpha sin beta is

If alpha+beta=90^(@),alpha=2beta , then find the value of cos^(2)alpha+sin^(2)beta .

.If alpha+beta=90^(@), show that sqrt(cos alpha*csc beta-cos alpha*sin beta) = sin alpha