Question

2.
Find the value of
(i) sin(-210°)
(ii) cos(-30°)
(iii) sec(-135°)
(iv) tan (-135°)
(v) cosec(-120°)
(vi) cot(–60°)​

Answer 1

Answer:

sin 120° = sin (1 × 90° + 30°) = cos 30° = √32;

cos 120° = cos (1 × 90° + 30°) = - sin 30° = - 12;

tan 120° = tan (1 × 90° + 30°) = - cot 30° = - √3;

csc 120° = csc (1 × 90° + 30°) = sec 30° = 2√3;

sec 120° = sec (1 × 90° + 30°) = - csc 30° = - 2;

tan 120° = tan (1 × 90° + 30°) = - cot 30° = - √3;

cot 120° = cot (1 × 90° + 30°) = - tan 30° = - 1√3.

Answer 2

Answer:

Step-by-step explanation:

i)sin(-210) = -sin 210 = -(sin(180+30))= -(-sin 30) = sin 30= $\frac{1}{2}$

ii)cos(-30) = cos 30 = $\frac{\sqrt{3} }{2}$

iii)sec(-135) = sec(180+45) = sec 45 = $\sqrt{2}$

iv)tan(-135) = -(tan(180-45)) = -(-tan 45) = tan 45 = 1

v)cosec(-120) = -cosec120 = -(cosec (90+30)) = -sec 30 = -$\frac{2}{\sqrt{3} }$

vi) cot(-60) = -cot 60 = - $\sqrt{3}$