Still have math questions?

Trigonometry
Question

Trigonometric Substitution In Exercises $$53 - 56$$ , use the trigonometric substitution to write the algebraic expression as a trigonometric function of $$\theta$$ , where

$$0 < \theta < \pi / 2$$ . 53. $$\sqrt { 9 - x ^ { 2 } } , x = 3 \cos \theta$$

55. $$\sqrt { x ^ { 2 } - 4 } , x = 2 \sec \theta$$

53. $$3 \sqrt { ( 1 + \cos ( \theta ) ) ( 1 - \cos ( \theta ) ) }$$
55.  $$2 \sqrt { ( \sec ( \theta ) + 1 ) ( \sec ( \theta ) - 1 ) }$$