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Find the values of p so that the equatio...

Find the values of `p` so that the equation `2cos^2x-(p+3)cosx+2(p-1)=0` has a real solution.

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We have `2cos^2x-(p+3)cosx+2(p-1)-0`
`=cosx=((p+3)pmsqrt((p+3)^2-8(2p-2)))/4`
`=((p+3)pm(p-5))/4`
`=(p-1)/2,2`
`rArr cosx=(p-1)/2 " (as"cosxne2")"`
Since `-1lecosxle1`
`rArr-2lep-1le2`
`rArr-1leple3`
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CENGAGE-TRIGONOMETRIC FUNCTIONS -SINGLE CORRECT ANSWER TYPE
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