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If sin theta and - cos theta are the ...

If sin `theta ` and - cos `theta ` are the roots of the equation `ax^2-bx-c=0` where a, b and c the side of a triangle ABC , then cos B is equal to :-

A

`1-(c )/(2a)`

B

`1-(c )/(a)`

C

`1+( c)/(2a)`

D

`1+ (c )/(3a)`

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The correct Answer is:
C
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ALLEN-Solutions of Triangle & Binomial Theorem-EXERCISE-I
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