Question

Find the value of A. Sin 120 degrees B. Tan 150 degrees C. Cos (-135 degrees) D. Sec 300 degrees E. Sin 240 - cos 330 degrees

Answer 1

sin 120 = 2 sin 60 cos 60 = 2 * root(3)/2 * 1/2

Tan 150 = tan (180-30) = - tan 30 = - 1/root(3)

Cos (-135) = Cos 135 = - Cos (180-135) = - Cos 45 = -1/root(2)

Sec 300 = 1/cos 300 = 1/Cos (360-60) = 1/Cos 60 = 2

Sin 240 - cos 330 =  Sin (180+60)  - Cos (360-30) = - sin 60 - cos 30 = 0

Answer 2

Sin 120 = 2 sin 60 cos 60
= 2 × √3/2 × 1/2
=√3/2

B. Tan 150
 = tan (180-30)
 = - tan 30
 = - 1/√3

C . Cos (-135)
 = Cos 135
= - Cos (180-135)
 = - Cos 45
= -1/√2

D . Sec 300
 = 1/cos 300
 = 1/Cos (360-60)
 = 1/Cos 60
 = 2

E . Sin 240 - cos 330
 =  Sin (180+60)  - Cos (360-30)
= - sin 60 - cos 30
= 0