Pre calculus. i have a test 2marrow and have a question. If you have the sec how can u find sin.

Answer 1

sec(x) = 1/cos(x) ==> cos(x) = 1/sec(x)

sin²(x) + cos²(x) = 1 ==> sin²(x) = 1 - cos²(x) ==> sin(x) = +- √ [1 - (1/sec(x))² ]

You cannot resolve the +- sign ambiguity unless you know which quadrant x lies in