Question

If `tan x=3`, what are sin x and cos x?

Answer 1

If `tan(x) =3` then there are two possible configurations:

from which it follows that
`sin(x) = 3/sqrt(10)` or `sin(x) = -3/sqrt(10)`
and
`cos(x) = 1/sqrt(10)` or `cos(x) = -1/sqrt(10)`