Question

resolva a equação 2sen²x + senx - 1 = 0​

Answer 1

Resposta:

2sen² x +sen x - 1 = 0

2x²+ x - 1 = 0

Δ = b²-4.a.c

Δ = 1² - 4.(2).(-1)

Δ= 1+8

Δ=9

x= -b ±√Δ

        2a

x= -1 +√9 = 1+3=2 = 1

        2               2

S= {x ∈ R | x=  π + K.2π, k ∈ Z}    

                       2