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已知函数f(x)=2根号3sinxcosx+cos2x 求f(π/6)的值
人气:385 ℃ 时间:2019-08-19 14:40:55
解答
f(x)=2√3sinxcosx+cos2x
=√3sin2x+cos2x
=2(√3/2sin2x+1/2cos2x)
=2sin(2x+π/6)
f(π/6)=2sin(2*π/6+π/6)
=2sin(3*π/6)
=2sinπ/2
=2��X�ʣ�0����/4��������f(x)��ֵ�򡣡�����ллX∈(0,π/4)2x∈(0,π/2)2x+π/6∈(π/6,π/2+π/6)1/2<=sin(2x+π/6)<=11<=2sin(2x+π/6)<=2∴f(x)的值域是[1,2]
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