赞 zcbsydddcvm 幼苗
共回答了11个问题采纳率：100% 举报
f(x)=(sinx+cosx)sinx-2sin(x+π/4)sin(x-π/4)=sin^2x+sinxcosx-(sinx+cosx)(sinx-cosx)
=sinxcosx+cos^2x =(sinxcosx+cos^2x )/(sin^2x+cos^2x)=(tanx+1）/(tan^2x+1)
f(a)=3/5
=sinxcosx+cos^2x =(sinxcosx+cos^2x )/(sin^2x+cos^2x)=(tanx+1）/(tan^2x+1)
f(a)=3/5
1年前
1
sunnyguo816 幼苗
共回答了2个问题 举报
f(x)=(sinx+cosx)sinx-2sin(x+π/4)sin(x-π/4)
=sin^2+sinxconx-(sinx+cosx)(sinx-cosx)
=sin^2+sinxconx-sinx^2+cosx^2
=(tanx+1)/cos^2
f(a)=(tana+1)/coxa^2
=3/5
=sin^2+sinxconx-(sinx+cosx)(sinx-cosx)
=sin^2+sinxconx-sinx^2+cosx^2
=(tanx+1)/cos^2
f(a)=(tana+1)/coxa^2
=3/5
1年前
2
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