sin(12分之π)-根3×cos(12分之π)的值

sin(12分之π)-根3×cos(12分之π)的值


sin(π/12)-√3cos(π/12)
=2(1/2sin(π/12)-√3/2cos(π/12))
=2sin(π/12-π/3)
=2sin(-π/4)
=-√2



f(x)=cos²;(π/6)+sinπ/6cosπ/6


f(x)=[cos(派/6)]^2+sin(派/6)cos(派/6)
=[(根號3)/2]^2+[(1/2)*(根號3)/2]
=(3/4)+(根號3)/4
=(3+根號3)/4.



求極限limX平方-5/X平方-3,X趨近與正無窮


上下除以x²;
原式=lim(1-5/x²;)/(1-3/x²;)
=(1-0)/(1-0)
=1