Question

Which expression is equivalent to (cos x)(tan(–x))?

A. -sin x
B. sin x
C. -csc x
D. csc x

Answer 1

the answer to this is A

Answer 2

The tan(-x) is the same thing as -tan(x). The tangent function is also the same thing as sin(x)/cos(x), right? So let's rewrite that tan in terms of sin and cos:

`[cos(x)][tan(-x)]` is the same as
`[cos(x)][ -(sin(x))/(cos(x))]`
We can now cancel out the cos(x), which leaves us only with -sin(x) remaining. So your answer is A.