Multiple Choice Please select the best answer and click subm

Multiple Choice: Please select the best answer and click \"submit.\" On the unit circle, which of the following angles has the terminal point coordinates (- square root 2 / 2 - square root 2 / 2)?

Solution

Whave have, x= - (sqrt(2))/ 2

and            y = - (sqrt(2))/ 2

Since both x and y are negative, hence point must be in 3rd quadrant

Therefore angle theta = pi+ arctan (y/x)

                             =   pi + arctan (- (sqrt(2))/ 2)/ (- (sqrt(2))/ 2)

                              = pi + arctan 1

                             = pi +pi/4 = 5pi/4 = 5*180/4 = 225

C is the correct option