`If " "a cos phi = b cos theta," show that " a tan theta + b tan phi = (a+b) tan ((theta + phi)/2)`

If (1 + tan theta) (1+ tan phi) = 2, then theta + phi =

If cos theta = n cos ( theta + 2 phi) "show that"(n+1) tan ( theta + phi)= (n-1) cot phi

If : sin (theta + phi) = 2 sin (theta - phi), "then" : tan theta = A) tan phi B) 2 tan phi C) 3 tan phi D) 4 tan phi

Find the value of k from the following relations : 3 ( cos 2 phi - cos 2 theta) = 1- cos 2 theta cos phi , tan theta = ktan phi "where" theta and phi" are acute angles"

If (1+tan theta)(1+tan phi)=2 then theta+phi=

If (1+tan theta)(1+tan phi)=2then(theta+phi) is

If 2 tan theta = cot phi, "show that" cos(theta - phi) = 3 cos ( theta + phi).

If cos(theta+phi)=m cos(theta-phi) then tan theta is equal to

If sin theta = k sin (theta + phi),"show that", tan(theta + phi) = (sin phi)/(cos phi -k).