Question

Hello guys ❤️

Find the values of the following trigonometric ratios:
(i) cos 225°
(ii) sin 690°
(iii) tan (-390°)

Answer Step-Wise !!​

Answer 1

Answer:

✨HELLO✨

(i) For angle 225°, terminal side of angle lies in third quadrant where cosine function is negative.

So, cos 225° = cos(90°×2 + 45°) = -cos 45° = -1/√2

(ii) For angle 690°, terminal side of angle lies in fourth quadrant where sine function is negative.

So, sin 690° = sin(90°× 7 + 60°) = -cos60° = -1/2

(iii) For angle 390°, terminal side of angle lies in first quadrant where tan function is positive.

So, tan (-390°) = -tan 390° = -tan (90°×4 + 30°) = -tan 30° = -1/√3

❤️Hope it will help you.❤️

Answer 2

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