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Two circles with radii `r_1 and r_2, r_1 gt r_2 ge 2, ` touch other externally. If `'alpha'` be the angle between direct common tangents ,then

A

` alpha = sin ^(-1) ((r_1 +r_2)/( r_1-r_2)) `

B

` alpha = 2 sin ^(-1) ((r_1-r_2)/( r_1+r_2))`

C

` alpha =sin ^(-1) ((r_1-r_2)/( r_1+r_2)) `

D

`alpha =sin ^(-1) ((r_1)/(r_1))`

Text Solution

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The correct Answer is:
B
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