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共回答了46个问题 举报
f(x)=向量a*b-1
=（2sinx，cosx）*（√3cosx，2cosx）-1
=2√3sinxcosx+2cos^2x-1
=√3sin2x+cos2x
=2[sin2x*√3/2+cos2x/2]
=2[sin2xcosπ/6+cos2xsinπ/6]
=2sin(2x+π/6)
对称轴为2x+π/6=π/2+2kπ
[x|x=π/6+kπ,x∈N]
=（2sinx，cosx）*（√3cosx，2cosx）-1
=2√3sinxcosx+2cos^2x-1
=√3sin2x+cos2x
=2[sin2x*√3/2+cos2x/2]
=2[sin2xcosπ/6+cos2xsinπ/6]
=2sin(2x+π/6)
对称轴为2x+π/6=π/2+2kπ
[x|x=π/6+kπ,x∈N]
1年前
1
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