The Pythagorean identity states that: cos²(θ) + sin²(θ) = 1, which is a fundamental trigonometric identity.
cos(π/3) corresponds to cos(60°), and the value of cos(60°) is 1/2.
Use the Pythagorean identity:
sin²(θ) + cos²(θ) = 1.
(3/5)² + cos²(θ) = 1,
9/25 + cos²(θ) = 1,
cos²(θ) = 1 - 9/25 = 16/25,
cos(θ) = √(16/25) = 4/5.
The sine of 30° is a standard trigonometric value:
sin(30°) = 1/2.
The tangent of 45° is 1 because tan(45°) = sin(45°) / cos(45°) = 1/1 = 1.
