Astudent is given that point p(a, b) lies on the terminal ray of angle , which is between radians and 2 radians. the student uses the steps below to find cos . step 1 find the quadrant in which p(a, b) lies: p(a, b) is in quadrant iv. step 2 use the point and the pythagorean theorem to determine the value of r: , but since r must be positive, . step 3 determine cos . , where a and b are positive. which of the following explains whether the student is correct? the student made an error in step 3 because a is positive in quadrant iv; therefore, . the student made an error in step 3 because . the student made an error in step 2 because r is negative in quadrant iv; therefore, . the student made an error in step 2 because using the pythagorean theorem gives .