Express each of the following in terms of trigonometric ratios of angles between 0° to 45°:
(i) tan 81° + cos 72°
(ii) cot 49° + cosec 87°.
Answer :
(i) tan 81° + cos 72°
= tan (90° – 9°) + cos (90° – 18°)
= cot 9° + sin 18°
(ii) cot 49° + cosec 87°
= cot (90° – 41°) + cosec (90° – 3°)
= tan 41° + sec 3°
More Solutions:
- Prove the following: (sin A + cos A)2 + (sin A – cos A)2 = 2
- Simplify
- Find the value of sin2 θ + cosec2 θ.
- Prove that x2 + y2 = a2 + b2.
- Calculate all the six t-ratios for both acute………
- Find the values of: sin ∠ABC
- Find tanθ – cotθ in terms of p and q.
- Given 4 sin θ = 3 cos θ, find the values of:
- Prove that 3 sin 0 – 4 sin3 0 = 1.
- If (sec θ – tan θ)/ (sec θ + tan θ) = ¼, find sin θ.