Problem with Vibration and Waves AP French?

[Karim Habashy]

Hi All,

Kindly see the attached Pictures.

I think COB is not 90 - δ/2
But
COB is 90-δ

Can someone confirm.

Thanks.

 

[nasu]

No. It is over 2.
Why do you think is not so?

 

[Karim Habashy]

∠'CBO' = 90 and ∠'OCB' = δ
∴ from the Δ 'OCB' we find that :
∠'COB' = 180-90-δ = 90-δ

 

[nasu]

Why do you think CBO is 90? These triangles seem to be isosceles and not right-angle. Aren't these triangles all equal?
Otherwise how do you know that the angle at OCB is delta?

 

[Karim Habashy]

Ya, you r right, i got it -_- .
My mind played tricks on me, i had the wrong mental image of an inscribed polygon in a circle, haven't done geometry in sometime.

Thanks