Problem

Werg22

http://img338.imageshack.us/img338/9397/circle9sr.jpg

The question goes;

B is the center of the arc AC and BD is perpendicular to AE, proove that
AD = DE + EC

I've been on it for hours now and I can't find anything...

amcavoy

The way I am thinking of is fairly long, but here it is:

Use the law of cosines. Note that angle BAC=BCA.

[EC]²=[AE]²+[AC]²+2cosθ

where θ is the angle EAC. Try working it out and let me know if you get stuck.

Alex

amcavoy

Sorry, that should be ...-2[AE][AC]cosθ in the above equation.

Alex