cant see how to figure this one out

Question

Use an Addition or Subtraction Formula to write the expression as a trigonometric function of one number.

cos 11° cos 49° − sin 11° sin 49°

        Find its exact value.

 

Answer 1

The trigonometric expression is .

Subtraction formula for trigonometric identity is .

Substitute and in the trigonometric formula.

The value of trigonometric expression is .