If cot `alpha cot beta=2` show that `(cos(alpha+beta))/(cos(alpha-beta))=1/3`

If tan alpha=k cot beta then (cos(alpha-beta))/(cos(alpha+beta)) is

If sin alpha+sin beta=a and cos alpha+cos beta=b show that sin(alpha+beta)=(2ab)/(alpha^(2)+beta^(2))

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

If tan alpha=x+1,tan beta=x-1, show that 2cot(alpha-beta)=x^(2)

If tan alpha=x+1,tan beta=x-1, show that 2cot(alpha-beta)=x^(2)

If tan alpha=x+1,tan beta=x-1, show that 2cot(alpha-beta)=x^(2)

If cos alpha+cos beta=0=sin alpha+sin beta, then cos2 alpha+cos2 beta is equal to (a)-2sin(alpha+beta)(b)-2cos(alpha+beta)(c)2sin(alpha+beta)(d)2cos(alpha+beta)