Jana is proving that the following trigonometric identity is true: cos(−θ)⋅tanθ=sinθ which step would be the first line of her proof? cos(−θ)⋅tanθ=sin(−θ) cosθ⋅tan(−θ)=sinθ cosθ⋅tanθ=sinθ cos(−θ)⋅tan(−θ)=sinθ

The first line of her proof is  

Step-by-step explanation:

The given trigonometric identity is .

Jana has to recall that, the cosine function is an even function.

For that matter, .

Jana has to apply this property by substituting for in the given identity to obtain,

.

Note that, the sine and the tangent functions are odd functions, therefore,

and

Hence, the correct answer is option C.

0.32

step-by-step explanation:

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