Verify that the equations below are trigonometric identities. 4. cot O + tan 0 = 2csc20 5. cos 40 = 8cos 4 0-8cos2 0+1 Verify that each of the following equations is an identity. cos(a -b) - = tan a + cot b 7. sin(a + b) = tana + tanb cos a sin b cos a cos b Page 658 Pre-AP* CalculusName Date Period Day #76 Homework For problems I and 2, an angle 0 is described. Draw and label the reference triangle for each angle and then find the values of sin 20, cos 20, and tan 20. 1. cos 0 =-13 - and 0 terminates in Quadrant III 2. sin 0 = -3 and 0 terminates in Quadrant IV 3. Verify that the equation below is a trigonometric identity. sin 20 = cot 0 1 - cos 20 Page 657 Pre-AP* Calculus8. (sin @ + cos @) = sin 20+1 9. tan Osin 20 = 2-2cos20 10. Sin 20 2 sin 0 11. cos 8 Sec e sin @ cot 0 = sin2 0+ cos20 12. cscosin 20-sec 0 = cos 20sec 0 13. 2 tan B = sec2 B sin 2B Page 659 Pre-AP* Calculus