Question

Find the exact value of the expression:
cos [tan^-1 (-4/7)]

Answer 1

The tangent is negative so it must be in quadrant 2 or 4. Draw a picture in one of those quadrants.

Answer 2

Find the missing side of the triangle and remember that cosine is side adjacent over hypotenuse. Negative in 2nd quadrant, positive in fourth

Answer 3

Would you know how to do it dealing with the unit circle? She hasn't used graphs o;