问题标题:
【1、已知3sin^2α+2sin^2β=2sinα,则sin^2α+sin^2β的取值范围是_.2、若-π/3≤x≤π/3,求函数y=sin^2x+4sin^2x/2的值域.】
问题描述:
1、已知3sin^2α+2sin^2β=2sinα,则sin^2α+sin^2β的取值范围是_.
2、若-π/3≤x≤π/3,求函数y=sin^2x+4sin^2x/2的值域.
戴永康回答:
1,因为3sin^2α+2sin^2β=2sinα的2(sin^2α+sin^2β)=2sinα-sin^2α所以sin^2α+sin^2β=-1/2(sin^2α-2sinα)=-1/2(sinα-1)^2+1/2所以,sin^2α+sin^2β的取值范围是[0,1/2];2,y=sin^2x+4sin^2x/2=sin^2x+...
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