Find the value of (4/3) tan ² 30 ^o +sin ² 60 ^o – 3 cos ² 60 ^o + (3/4) tan ² 60 ^o –2 tan ² 45 ^o .

27
If cosec θ - sin θ = a, sec θ - cos θ = b, prove that a ²b ²(a ²+b ²+ 3) = 1.
28
Prove that (sin θ + sec θ) ²+ (cos θ + cosec θ) ²=(1 + sec θ cosec θ) ².
30
Find the value of 4(sin ⁴30 ^o+ cos ⁴60 ^o)– 3(cos ²45 ^o+ sin ²90 ^o).
31
Prove that: