Question

高中三角函数证明y=-t^2/2 + 1/2

Answer 1

证明：

y=[(cos^2θ-sin^2θ)/2sinθcosθ ] * tanθ

分子分母同时除以cos²θ

=[(1-tan²θ)/(2tanθ)]*tanθ

=(1-tan²θ)/2

=-(tan²θ)/2+1/2

=-t²/2+1/2