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In DeltaABC, a=3,b=4,c=2, then prove tha...

In `DeltaABC`, a=3,b=4,c=2, then prove that: `cosA/2 = (3sqrt(6))/(8)`

Text Solution

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`s=(a+b+c)/(2)=(3+4+2)/(2)=9/2`
and `cosA/2 = sqrt(s(s-a))/(bc)`
`=sqrt((9/2(9/2-3))/(4 xx2))`
`=sqrt((9 xx 3))/sqrt(4 xx 4 xx 2)=(3sqrt(6))/(8)` Hence Proved.
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