Use the trigonometric substitution to write the algebraic eq
Use the trigonometric substitution to write the algebraic equation as a trigonometric equation of , where /2 < < /2.
5 =sqrt( 25 x^2) , x = 5 sin
Find sin(theta), cos(theta).
Solution
5 = sqrt ( 25 - x^2 )
x = 5 sin theta
substituting the value of x
5 = sqrt ( 25 - ( 5 sin theta )^2)
5 = sqrt ( 25 - 25 sin^2 theta )
5 = sqrt ( 25 ( 1 - sin^2 theta ))
1 - sin^2 theta = cos^2 theta
5 = sqrt ( 25 * cos^2 theta )
5 = + - 5 cos theta
cos theta = + - 1
sin theta = 0
