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In any DeltaABC , prove that: (sinB)/...

In any ` DeltaABC` , prove that: `(sinB)/(sinC)=(c-acosB)/(b-acosC)`

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`R.H.S. = (c-acosB)/(b-acosC)`
From projection formulas,
`c = acosB + bcosA`
`b = acosC+c cosA`
`:.(c-acosB)/(b-acosC) = (acosB + bcosA-acosB)/(acosC+c cosA-acosC)`
`=(bcosA)/(c cosA)`
`=b/c`
`L.H.S. = sin B/sinC`
...
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