(i) sin 300° = sin(360° – 60°) 

[For 360° – 60°. No change in T-ratio. 300° lies in 4th quadrant ‘sin’ is negative] 

= -sin 60°

= – \(\frac{\sqrt{3}}{2}\)

(ii) cos(-210°) = cos 210° (∵ cos(-θ) = cos θ) 

[∵ 180 + 30°. No change in T-ratio. 210° lies 3rd quadrant ‘cos’ is negative] 

= cos(180° + 30°) 

= -cos 30°

= – \(\frac{\sqrt{3}}{2}\)

(iii) sec 390° = sec(360° + 30°) 

= sec 30° 

= \(\frac{1}{cos 30°}\)

= \(\frac{1}{\frac{\sqrt{3}}{2}}\)

= \(\frac{2}{\sqrt{3}}\)

(iv) tan(-855°) = -tan 855° (∵ tan(-θ) = – tan θ) 

[∵ Multiplies of 360° are dropped out. For 180° – 45°. No change in T-ratio. 180° – 45° lies in 2nd quadrant ‘tan’ is negative] 

= -tan(2 x 360° + 135°) 

= -tan 135° 

= -tan(180° – 45°) 

= -(-tan 45°) 

= -(-1) 

= 1

(v) cosec 1125° = cosec(3 x 360°+ 45°) 

= cosec 45° 

= \(\frac{1}{sin45°}\)

= \(\frac{1}{\frac{1}{\sqrt{2}}}\)

= √2