已知sin(4x+π/3)-4sin(2x-5π/6)+cos(2x+π/6)+2=0,
问题描述:
已知sin(4x+π/3)-4sin(2x-5π/6)+cos(2x+π/6)+2=0,
答
设a=2x+π/6sin(4x+π/3)-4sin(2x-5π/6)+cos(2x+π/6)+2=0sin2(2x+π/6)-4sin(2x+π/6-π)+cos(2x+π/6)+2=0sin2a-4sin(a-π)+cosa+2=0sin2a+4sina+cosa+2=02sinacosa+4sina+cosa+2=02sina(cosa+2)+cosa+2=0(2sina+...