Math Forum :: View topic – 求證:a sinB=b sinA.

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Joined: 15 Apr 2004Posts: 12

Posted: Fri Apr 16, 2004 11:40 pm    Post subject: 求證:a sinB=b sinA.

在△ABC中,∠A、∠B均為銳角,∠A、∠B所對的邊為a、b,求證:a sinB=b sinA.


Frequent VisitorJoined: 12 Feb 2004Posts: 213

Location: Hong Kong

Posted: Sat Apr 17, 2004 2:09 am    Post subject: Re: 求證:a sinB=b sinA.

Hilda wrote:

在△ABC中,∠A、∠B均為銳角,∠A、∠B所對的邊為a、b,求證:a sinB=b sinA.

Hilda, A and B are acute angle is useless, this is a result of cosine law: a/sinA=b/sinB=c/sinC=2R, where R is the radius of circumcircle of ABC.

P.S.You any prove it by drawing the altitudes.


Joined: 15 Mar 2005Posts: 8

Posted: Tue Mar 15, 2005 9:59 pm    Post subject:

It should be Sine Forumla.

From the figure, you can find that

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