作业帮1.若0
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1.若0
1.若0
1.若0
1）
tan(x-y)=(tanx-tany)/(1+tanxtany)
=2tany/(1+3tan^2y)
=2/(1/tany+3tany)
≤2/2√(1/tany*3tany)
=1/√3
=√3/3
=tanπ/6
x-y的最大值为：π/6
2)
（x^2/y^2）+(y^2/x^2)=（x/y+y/x)^2-2
3[（x^2/y^2）+(y^2/x^2)]-8[(x/y)+(y/x)]+10
=3[(x/y+y/x)^2-2]-8(x/y+y/x)+10
=3(x/y+y/x)^2-8(x/y+y/x)+4
=3[(x/y+y/x)-4/3]^2-4/3
≥3[2-4/3]^2-4/3
=0
3[（x^2/y^2）+(y^2/x^2)]-8[(x/y)+(y/x)]+10的最小值为:0