If `sinx+siny=a` & `cosx+cosy=b` then which of the following may be true

If 1 + cos x cos y + sin x sin y = 0 , then which of the following is / are true 1. cosx + cosy = 0 2. sinx + siny = 0 3. sinx + cosy = 0 chose the correct option from the code given below

If sinx+siny=p,cosx+cosy=q then sec(x+y)=

If sin x+siny=a, cosx+cosy=b , then what is the value of cos(x-y) ?

If sinx+siny=1/2 and cosx+cosy=1 , then tan(x+y)=

I. x=y II. 9(x+y)=pi III. cosx=cosy If 0ltx, ylt(pi)/(2) , and sinx=cosy, then which of the statements above must be true?

If sinx/siny=1/2 and cosx/cosy=3/2 then sqrt(8+sec^2y)=

If sinx+siny geq cosa cosx, AA x in R then siny+cos a=