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If in a DeltaABC,a=6cm,b=8cmandc=10cm, ...

If in a `DeltaABC,a=6cm,b=8cmandc=10cm`, then the value of sin 2A is

A

`6//25`

B

`8//25`

C

`10//25`

D

`24//25`

Text Solution

Verified by Experts

The correct Answer is:
D
`becausecosA=(b^(2)+c^(2)-a^(2))/(2bc)=((8)^(2)+(10)^(2)-(6)^(2))/(2xx8xx10)=(128)/(160)=(4)/(5)`
`rArrsinA=sqrt(1-((4)/(5))^(2))=(3)/(5)`
`thereforesin2A=2sinAcosA=2xx(3)/(5)xx(4)/(5)=(24)/(25)`
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