Question

在三角形ABC中 角BAC=90 AD垂直BC DE垂直AB DF垂直AC 已知BE=m CF=n 求三角形ABC的面积

Answer 1

设AC=x，AB=y，∠C=a

CD=xcosa

CF=CDcosa=xcosa^2=n

BD=ysina

BC=BDsina=ysina^2=m

x/y=tana=sina/cosa

BC/CF=m/n=y/x*sana^2/cosa^2=x/y=tana

tana^2=m^2/n^2=sina^2/cosa^2

sina^2/(s...