cos480° sin225°诱导公式应用

dsgyhqyzb2022-10-04 11:39:541条回答

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HAPPY小臭臭共回答了19个问题 | 采纳率94.7%: cos480° sin225°
=cos(360+120) sin(180+45)
=cos120*(-sin45)
=-1/2*(-根号2/2)
=根号2 /4; 1年前

csc480°= 1-2i/3+i= csc480°= 1-2i/3+i= 1csc480°= 21-2i/3+i= 3Given a1=1,an=2an-1（见图片）,then the sum of the first 10 terms of the sequence is 4If the center of circle x²+y²+ax+by-5=0 is（1,1/2),then the radius is 5The standard equation of a parabola with focus(1,2),and directrix y=6 is 6In△ABC,AC=1,AB=根号3,角B=30°,then the area of △ABCis? 7Given（x-1）²-16（y+2）²=16,find the center,thefocus,the vertex,the transverse axis lenth and the conjugate axis length,the eccentricity,the asymptotes. file:///C:/Documents%20and%20Settings/Administrator/%E6%A1%8C%E9%9D%A2/%E6%9C%AA%E5%91%BD%E5%90%8D2.JPG 笑zz1年前1: 安其文共回答了15个问题 | 采纳率93.3%

csc480°= csc120°=1/sin120°=1/(√3/2)=2/√3=2√3/3
1-2i/3+i= (1-2i)(3-i)/(3+i)(3-i)
=(3-7i-2)/10
=(1-7i)/10

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