设(m+i)*4(4次方)属于R,则实数m=?
n*** 2006-07-16 11:08:25 举报
(m+i)^4 =m^4+4m^3i+6m^2i^2+4mi^3+i^4 =(m^4-6m^2+1)+(4m^3i-4mi) =(m^4-6m^2+1)+(4m^3-4m)i 因为m为实数,故4m^3-4m=0 解得m=0或1或-1
1/5÷2/3=1/5×3/2=3/10小时
(38+41)x2.5=197.5千米
连接OC;∵AB=4,O是AB中点,且△ABC是直角三角形,∴OC=2...