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In any triangle A B C , prove that:Delt...

In any triangle `A B C ,` prove that:`Delta=(b^2+c^2-a^2)/(4cota)` .

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`R.H.S. = (b^2+c^2-a^2)/(4cotA)`
` = (b^2+c^2-a^2)/(4cosA/sinA)`
` = (b^2+c^2-a^2)sinA/(4cosA)`
`=1/4(b^2+c^2-a^2)sinA/((b^2+c^2-a^2)/(2bc))`
`= 1/4*2bc*sinA`
`=1/2bcsinA = Delta(`Area of `Delta ABC).`
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