tanx 13 Defined Defined Exercise 4.6 1. Using the unit circle, find the values of the sine, cosine and tangent functions of the following quadrantal angles: a. 0° b. 450° c. 540° d. 630° 214 Unit 4 Trigonometric Function b. Fill in the blank with numbers. degree-360°-450-270° |-180°-90° | 90° | 180° 720° - sinx -------- cosx tanx - ----- Sign of trigonometric functions Let P(a,b) be a point on the unit circle with center at the origin such that m(LAOP) = x. If m(LAOQ) = -x, the coordinate of the point Q(a,b)(see Figure 4.18). Therefore, cos(-x) = cosx and sin(-x) = -sinx. Since for every point P(a, b) on the unit circle where -1≤as1 and -1 ≤ b ≤1, we have -1​​