Question

3 I write the values of sin 600°, cos 330°, cos 120°, sin 150° ) .​

Answer 1

Answer:

(1) -1

Solution:

sin 600° cos 330° + cos 120° sin 150°

= sin(360° + 240°) cos(360° – 30°) + cos(90° + 30°) sin(180° – 30°)

= sin 240° cos 30° – sin 30° sin 30°

= sin(270° – 30°) cos 30° – (1/2)(1/2)

= -cos 30° cos 30° – (1/4)

= -(√3/2)(√3/2) – (1/4)

= -(3/4) – (1/4)

= -4/4

= -1

Answer 2

sin 600°

= sin (630° - 30°)

= sin ( 7 × 90 - 30°)

= sin ( 7 × π/2 - 30°)

= - sin (30°)

= - 1/2

cos 330°

= cos (360° - 30°)

= cos ( 4 × 90° - 30°)

= cos ( 4 × π/2 - 30°)

= cos ( 2π - 30°)

= cos 30°

= √3/2

cos 120°

= cos ( 180° - 60° )

= - cos 60°

= - 1/2

sin 150°

= sin ( 180° - 30° )

= sin 30°

= 1/2

Sorry, I am unable to explain you each of the steps properly. Please refer to "Subject Teacher's YT channel" to understand the concept properly. Check the video on Trigonometry of class 11th.