Question

tan2Θ=-2√2,π

Answer 1

2cos^2Θ/2-sinΘ-1 / √2sin(Θ+π/4) =(cosΘ-sinΘ) /(cosΘ+sinΘ) {在分子和分母上同时除以cosΘ}

=(1-tanΘ) / (1+tanΘ)

tan2Θ=-2√2 =2tanΘ / (1-tan^2 Θ) 解得 tanΘ =√2或-√2/2

tanΘ =√2时 原式 = 2√2 -3

tanΘ =-√2/2时 原式 = 3 + 2√2