When given a trigonometric ratio, and asked to find another ratio, we draw a right triangle as shown in the picture.
From the pythagorean theorem we find the length of AB:
the numerical value of
cos∅=adjacent side/hypotenuse=
since sec∅=1/cos∅, and sec∅ is negative, then cos∅ is also negative.
Answer:
cos∅=
From the pythagorean theorem we find the length of AB:
the numerical value of
cos∅=adjacent side/hypotenuse=
since sec∅=1/cos∅, and sec∅ is negative, then cos∅ is also negative.
Answer:
cos∅=