tanx+sinx=sinx/cosx +sinx=1（sinx+sinxcosx）/cosx =1sinx+sinxcosx=cosxsinxcosx=cosx-sinx=√2cos（π/4 +x）1/2 sin2x =√2cos（π/4 +x）sin2x =2√2cos（π/4 +x）两边平方 sin²2x =8cos²（π/4 +x...