Question

Express the trigonometric function in terms of its positive acute reference angle. cos298° = cos

Answer 1

298* falls in quadrant 4 is 0* is the positive x-axis. In quadrant 4, cos is positive. Therefore, we simply need to calculate the acute angle,x, that correlates to 298*.

360 = 298 + x
62 = x

Therefore, we have :

cos(298*) = cos(62)

In case you need to know :

sin(298*) = - sin (62)
tan(298*) = - tan (62)

Since both sin and tan are negative in the fourth quadrant.