Complete the identity csc xsin x cos x A 2tan2x B sin x t

Complete the identity. csc x(sin x + cos x) = ? A. -2tan^2x B. sin x tan x C. sec x csc x D. 1 + cot x Find the exact value of the expression. sin 245 degree cos 5 degree - cos 245 degree sin 5 degree A. -1/2 B. -49/12 C. squareroot 3/2 D. -squareroot 3/2 Use trigonometric identities to find the exact value. tan 155 degree - tan 35 degree/1 + tan 155 degree tan 35 degree. A. -1/2 B. -squareroot 3/3 C. -squareroot 3 D. -2

Solution

12. csc x(sin x+cosx)

cscx sin x+csc x cos x =1+cot x

correct option is D.

13. sin 245 cos 5 -cos 245sin5

sin(245-5)=sin240=-sqrt3/2

correct option is C.

(tan 155-tan35)/(1+tan 55 tan 35)

tan (155-35)=tan 120=-sqrt3

correct option is C