in triangle abc a=12 b=16 and sinB=2/3 what is the measure of angle A in degrees还有:the equation x^2+2ix-4=0 has as its toota根号下5-1,-根号下5-1b根号下5-i,根号下5+ic根号下3-i,根号下5+id根号下3-i,根号下3+ie根号下3-1,-
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![in triangle abc a=12 b=16 and sinB=2/3 what is the measure of angle A in degrees还有:the equation x^2+2ix-4=0 has as its toota根号下5-1,-根号下5-1b根号下5-i,根号下5+ic根号下3-i,根号下5+id根号下3-i,根号下3+ie根号下3-1,-](/uploads/image/z/8648901-45-1.jpg?t=in+triangle+abc+a%3D12+b%3D16+and+sinB%3D2%2F3+what+is+the+measure+of+angle+A+in+degrees%E8%BF%98%E6%9C%89%EF%BC%9Athe+equation+x%5E2%2B2ix-4%3D0+has+as+its+toota%E6%A0%B9%E5%8F%B7%E4%B8%8B5-1%2C-%E6%A0%B9%E5%8F%B7%E4%B8%8B5-1b%E6%A0%B9%E5%8F%B7%E4%B8%8B5-i%2C%E6%A0%B9%E5%8F%B7%E4%B8%8B5%2Bic%E6%A0%B9%E5%8F%B7%E4%B8%8B3-i%2C%E6%A0%B9%E5%8F%B7%E4%B8%8B5%2Bid%E6%A0%B9%E5%8F%B7%E4%B8%8B3-i%2C%E6%A0%B9%E5%8F%B7%E4%B8%8B3%2Bie%E6%A0%B9%E5%8F%B7%E4%B8%8B3-1%2C-)
in triangle abc a=12 b=16 and sinB=2/3 what is the measure of angle A in degrees还有:the equation x^2+2ix-4=0 has as its toota根号下5-1,-根号下5-1b根号下5-i,根号下5+ic根号下3-i,根号下5+id根号下3-i,根号下3+ie根号下3-1,-
in triangle abc a=12 b=16 and sinB=2/3 what is the measure of angle A in degrees
还有:
the equation x^2+2ix-4=0 has as its toot
a根号下5-1,-根号下5-1
b根号下5-i,根号下5+i
c根号下3-i,根号下5+i
d根号下3-i,根号下3+i
e根号下3-1,-根号下3-i
in triangle abc a=12 b=16 and sinB=2/3 what is the measure of angle A in degrees还有:the equation x^2+2ix-4=0 has as its toota根号下5-1,-根号下5-1b根号下5-i,根号下5+ic根号下3-i,根号下5+id根号下3-i,根号下3+ie根号下3-1,-
第一题:可以用正弦定理得:sinA /a=sinB /b
所以得sinA=1/2,所以angle A=30度
第二题:由韦达定理得:方程根=[(-2i±根号下(4i²+16)]/2=-i±根号下3
所以选e
希望答案能满意.
我用中文回答了哈~^^
1、你可以从C点作AB边上的高CD,由sinB=2/3可以得到CD=8。然后在三角形ACD中,由于sinA=CD/AC=1/2,所以A=60°。
2、原式可化为(x+i)^2=3。因而解得答案为e。
^^~
a/sinA=b/sinB a=12 b=16 sinB=2/3 sinA=1/2 A=30