A:for; that
B:why; that
C:for; because
D:why; because
在△ABC中,a,b,c分别是角A,B,C的对边,若a2+b2=2014c2,则2tanA·tanBtanCtanA+tanB的值为( )
等腰三角形顶角是84°,则一腰上的高与底边所成的角的度数是( )