Question

用三角比诱导公式求值:cos(5π/3-θ)+sin(4π/3-θ)+cos(4π/3+θ)+

Answer 1

cos(5π/3-θ)+sin(4π/3-θ)+cos(4π/3+θ)+sin(2π/3+θ)

=cos(π/3+θ)-sin(π/3-θ)-cos(π/3+θ)+sin(π/3-θ)

=0