已知6sin2α=sin2,则tan(α-1)/tan(α+1)的值是多少?
热心网友
8sin2A=sin2tan(A-1)/tan(A+1)=[sin(A-1)/cos(A-1)]/[sin(A+1)/cos(A+1)]=sin(A-1)cos(A+1)/[sin(A+1)cos(A-1)]=1/2*[sin(2A)-sin2]/{1/2*[sin(2A)+sin2]}=(sin2A-6sin2A)/(sin2A+6sin2A)=-5sin2A/(7sin2A)=-5/7.
热心网友
已知6sin2α=sin2,则tan(α-1)/tan(α+1)的值是多少?tan(α-1)/tan(α+1)=sin(α-1)cos(α+1)/cos(α-1)sin(α+1)={1/2(sin(2α)-sin2)}/{1/2(sin(2α)+xin2}=-5sin/7sin2=-5/7