Simplifying Trigonometric Expressions

[striker7770]

Homework Statement

(Sin 2θ / sinθ) - (cos 2θ/ cos θ) = Sec θ

just trying to match one side to the other

Homework Equations

all trig identities

The Attempt at a Solution

broke down sin2θ into 2sinθ cosθ then reduced the sinθ in the denominator

giving me
sinθ cosθ - cos2θ / cosθ = Secθ

thanks

 

[stevenb]

Homework Statement

(Sin 2θ / sinθ) - (cos 2θ/ cos θ) = Sec θ

just trying to match one side to the other

Homework Equations

all trig identities

The Attempt at a Solution

broke down sin2θ into 2sinθ cosθ then reduced the sinθ in the denominator

giving me
sinθ cosθ - cos2θ / cosθ = Secθ

thanks

You are on the right track. It should be clear to you that the next step is to express cos(2t) as in terms of cos(t). What trig identity do you know that will do that?

Oh, and double check your expression, you may have made a silly math error there.