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If in DeltaABC , a = 4,b=3, A = 60^(@) ...

If in ` DeltaABC , a = 4,b=3, A = 60^(@)` then c is a root of the equation .

A

`c^(2) -3c -7=0`

B

`c^(2)-3c + 7=0`

C

`c^(2) - c + 7=0`

D

`c^(2) + 3c -7=0`

Text Solution

Verified by Experts

The correct Answer is:
A
`cos A = (b^(2)+c^(2)-a^(2))/(2bc)`
` cos 60^(@) = (3^(2) +c^(2) -4^(2))/(2(3)c) = 1/2 `
` c^(2) - 7 =3c`
`c^(2) -3c -7=0`
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