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Hilda
Joined: 15 Apr 2004Posts: 12
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Posted: Thu Apr 15, 2004 10:46 pm Post subject: 求BC和 S△ABC.
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在△ABC中，AB=2√3，∠A=45°，∠B=60°，求BC和 S△ABC.
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me
Frequent VisitorJoined: 12 Feb 2004Posts: 213
Location: Hong Kong
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Posted: Thu Apr 15, 2004 11:27 pm Post subject: Re: 求BC和 S△ABC.
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Hilda wrote:
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| 在△ABC中，AB=2√3，∠A=45°，∠B=60°，求BC和 S△ABC. |
AB/sinC=BC/sinA, so we can find BC. area of ABC=1/2(AB)(BC)sinB, so we can find it.
Another way is to drop a from A or B or C to the opposite side.
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Hilda
Joined: 15 Apr 2004Posts: 12
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Posted: Fri Apr 16, 2004 10:16 pm Post subject: Re: 求BC和 S△ABC.
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me wrote:
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Hilda wrote:
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| 在△ABC中，AB=2√3，∠A=45°，∠B=60°，求BC和 S△ABC. |
AB/sinC=BC/sinA, so we can find BC. area of ABC=1/2(AB)(BC)sinB, so we can find it.
Another way is to drop a from A or B or C to the opposite side.
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AB/sinC=BC/sinA中的sinC同sinA點求呀?比得AB=2√3一個值咋喎?
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Ellen
Frequent VisitorJoined: 28 Oct 2003Posts: 212
Location: CUHK
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Posted: Fri Apr 16, 2004 11:24 pm Post subject:
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so
and the easiset way you can find sinC is using a calculator to find [/tex]
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Hilda
Joined: 15 Apr 2004Posts: 12
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Posted: Fri Apr 16, 2004 11:30 pm Post subject:
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咁點解係AB/sinC=BC/sinA?
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Soarer
Frequent VisitorJoined: 18 Jan 2004Posts: 213
Location: Hong Kong
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Posted: Fri Apr 16, 2004 11:55 pm Post subject:
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Hilda wrote:
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| 咁點解係AB/sinC=BC/sinA? |
請問你幾年級?
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Hilda
Joined: 15 Apr 2004Posts: 12
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Posted: Fri Apr 16, 2004 11:59 pm Post subject:
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Soarer wrote:
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Hilda wrote:
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| 咁點解係AB/sinC=BC/sinA? |
請問你幾年級?
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中三~咁你呢?
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me
Frequent VisitorJoined: 12 Feb 2004Posts: 213
Location: Hong Kong
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Posted: Sat Apr 17, 2004 2:12 am Post subject:
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Hilda wrote:
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Soarer wrote:
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Hilda wrote:
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| 咁點解係AB/sinC=BC/sinA? |
請問你幾年級?
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中三~咁你呢?
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Soarer is f.5.
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newb1e
Joined: 05 Apr 2004Posts: 11
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Hilda
Joined: 15 Apr 2004Posts: 12
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Posted: Sat Apr 17, 2004 2:17 pm Post subject:
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唔該晒以上解答過我問題既人!!!
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