Question

The terminal ray of angle β , drawn in standard position, passes through the point (−5, 2√7) . What is the value of cos β ? Enter your answer, in simplest radical form, in the box.

Answer 1

Step-by-step explanation:

Draw the triangle formed by the ray.

The hypotenuse of the triangle is:

c² = a² + b²

c² = (-5)² + (2√7)²

c² = 25 + 28

c = √53

Therefore:

cos β = -5 / √53

Or, as a proper fraction:

cos β = -5√53 / 53