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设cos (x +π/4 )=3/5,17π/12
人气:158 ℃ 时间:2020-05-24 01:12:55
解答
∵17π/12sinx+cosx=-4√2/5.(2)∴由(2)-(1)得2sinx=-7√2/5 ==>sinx=-7√2/10由(2)+(1)得2cosx=-√2/5 ==>cosx=-√2/10故(sin2x+2sin²x)/(1-tan x)=(2sinxcosx+2sin²x)/(1-sinx/cosx)=2sinx(cosx+sinx)/(...
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