Q1 of 118 Page 5

Find the values of the following trigonometric ratios:

Given

⇒ 1755° = 90° × 19 + 45°

1755° lies in the fourth quadrant in which the cosine function is positive.

∴ cos 1755° = cos (90° × 19 + 45°)

= sin 45°

Find the values of the following trigonometric ratios:

prove that :

tan 225^o cot 405^o + tan 765^o cot 675^o = 0