Question

Find the values of 

(i) sin(480°) 

(ii) sin(-1110°) 

(iii) cos(300°) 

(iv) tan(1050°) 

(v) cot(660°) 

(vi) tan (19π/3) 

(vii) sin (-11π/3)

Answer 1

(i) sin(480°) = sin(360° + 120°) = sin 120° 

= sin(90° + 30°) = cos 30° = √3/2

(ii) sin(-1110°) = -sin(1110°) 

= – sin (360° × 3 + 30°) 

= -sin 30° = -1/2

(iii) cos(300°) = cos(270° + 30°) = sin 30° = 1/2

(iv) tan(1050°) = tan [3(360°) – 30°]

= - tan 30° = -1/√3

(v) cot(660°) = cot (360° × 2 – 60°)

= - cot 60° = -1/√3

(vi) tan (19π/3)

(vii) sin (-11π/3)