1. What is a Trigonometric Equation? A trigonometric equation is an equation where the unknown variable appears as the argument of one or more trigonometric functions (sine, cosine, tangent, etc.).
( \pi/8,\ 5\pi/8,\ 9\pi/8,\ 13\pi/8 ). Type 5: Equation with sine and cosine of the same angle Example: ( \sin x = \cos x ). ecuaciones trigonometricas 1 bachillerato
Let ( t = 2x ). Solve ( \tan t = 1 ). Principal value: ( t = \pi/4 ). Tangent period is ( \pi ): ( t = \pi/4 + k\pi ). Thus ( 2x = \pi/4 + k\pi \Rightarrow x = \pi/8 + k\pi/2 ). ( \pi/8,\ 5\pi/8,\ 9\pi/8,\ 13\pi/8 )
Case 1: ( \sin x = 0 \Rightarrow x = 0, \pi ) in ( [0, 2\pi) ). Case 2: ( \cos x = 1/2 \Rightarrow x = \pi/3,\ 5\pi/3 ) in ( [0, 2\pi) ). Solve ( \tan t = 1 )
Find ( k ) for ( 0 \le x < 2\pi ): ( k=0 \to \pi/8 ) ( k=1 \to \pi/8 + \pi/2 = 5\pi/8 ) ( k=2 \to 9\pi/8 ) ( k=3 \to 13\pi/8 ) ( k=4 \to 17\pi/8 = 2\pi + \pi/8 ) (too large).