①[4sin(α-π)-sin(3π/2-α)]/[3cos(α-π/2)-5cos(α-5π)] ②sin^2-2sin^2αcosα-cos^2α
①[4sin(α-π)-sin(3π/2-α)]/[3cos(α-π/2)-5cos(α-5π)] ②sin^2-2sin^2αcosα-cos^2α
数学人气:331 ℃时间:2020-05-09 00:40:16
优质解答
①用换角公式4sin(α-π)-sin(3π/2-α)=-4sina+cosa3cos(α-π/2)-5cos(α-5π)=3sina+5cosa同除以cosa:[-4sina+cosa]/[3sina+5cosa]=[-4tana+1]/[3tana+5]代入3得到-11/14②换成(sinθ)^2+(cosθ)^2就得到2(...
我来回答
类似推荐