Question

if sinx,cosx,tanx are in g.p then (cosx)^9+(cosx)^6+3(cosx)^5-1 equals

Answer 1

Please clarify what you mean by "g. p."

Answer 2

g.p. is geometric progression

Answer 3

New situation for me. What does it signify when you state that sin x, cos x and tan x are in geometric progression?

Answer 4

that is cosx=sinx*r
and tanx=cosx*r where r is the common ratio

Answer 5

also tanx=sinx*r^2
and \[\cos x =\sqrt{sinx*tanx}\]

Answer 6

If you state that that is cosx=sinx*r
and tanx=cosx*r where r is the common ratio, then it appears that the common ratio, r, is cos x / sin x, or cot x. Is that your reasoning?

Answer 7

yes

Answer 8

if that is the case, is it true, as you say, that tanx=sinx*r^2? Try verifying that.