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Let alpha and beta be the roots of the e...

Let `alpha` and `beta` be the roots of the equation `x^2+(2-costheta)x-(1+costheta)=0`, then

A

least value of `alpha^2 + beta^2` is 5

B

`alpha^2+beta^2` is least when `theta=2npi,n in I`

C

least value of `alpha^2+beta^2` is 6

D

`alpha^2+beta^2` is least when `theta=(2n+1)pi/2, n in I`

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A,B
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