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数学
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化简 sin(x-20°)+cos(x+70°)+sin(x+20°)sec(70°-x)
麻烦稍微写下过程呐.
人气:465 ℃ 时间:2020-03-25 03:54:39
解答
sin(x-20)=sin(110-x)
cos(x+70)=-cos(110-x)
sin(x+20)=cos(70-x)
sec(70-x)=1/cos(70-x)
原式=sin(110-x))-cos(110-x)+cos(70-x)*1/cos(70-x)=2^0.5sin(65-x)+1
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