Finding Value of trignometric functions, given angle
Value of sin, cos, tan repeats after 2π
Shifting angle by π/2, π, 3π/2 , 2π
Example 8
Ex 3.2, 9 Important
Ex 3.2, 8
Ex 3.2, 10 Important
Example 9 Important
Ex 3.2, 6
Ex 3.2, 7 Important
Example 10
Ex 3.3, 1 Important
Ex 3.3, 2 Important
Ex 3.3, 3 Important
Ex 3.3, 4
Ex 3.3, 8 Important
Ex 3.3, 9 Important You are here
Find values of sin 18, cos 18, cos 36, sin 36, sin 54, cos 54 Important
Finding Value of trignometric functions, given angle
Last updated at April 16, 2024 by Teachoo
Ex 3.3, 9 Prove cos (3π/2+𝑥) cos (2π + 𝑥)[cot (3π/2−𝑥) + cot (2π + 𝑥)] =1 Solving L.H.S. Now, cos (𝟑𝝅/𝟐 "+ " 𝒙) = sin x cos (2π + x) = cos x cot (2π + x) = cot x cot (𝟑𝝅/𝟐−𝒙) = tan x Now putting values in equation cos (3π/2+𝑥) cos (2π + 𝑥)[cot (3π/2−𝑥) + cot (2π + 𝑥)] = (sin x) × (cos x) × [tan x + cot x] = (sin x cos x) × [cot x + tan x] = (sin x cos x) × [𝒄𝒐𝒔𝒙/𝒔𝒊𝒏𝒙 + 𝒔𝒊𝒏𝒙/𝒄𝒐𝒔𝒙 ] = (sin x cos x) × [(〖(cos〗𝑥) × 〖(cos〗𝑥)+〖 (sin〗𝑥) × 〖(sin〗𝑥))/(sin𝑥 × 〖(cos〗𝑥))] = (sin x cos x) × [(𝐜𝐨𝐬𝟐𝒙 +〖 𝐬𝐢𝐧𝟐〗𝒙)/(𝒔𝒊𝒏𝒙 × 〖(𝒄𝒐𝒔〗𝒙))] = cos2𝑥 +〖 sin2〗𝑥 = 1 = R.H.S Hence proved