Ch 03 -Trigonometric Functions — Important Questions

1

tan 45° = sin45°/cos45° = (1/√2)/(1/√2) = 1.

1

sin²x + cos²x = 1 is the fundamental Pythagorean identity, derived from the unit circle equation x²+y²=1.

2π

sin x has period 2π (one full revolution on the unit circle). tan x has period π.

π

tan x has period π because tan(π+x)=tanx. sin and cos have period 2π.