You can put this solution on YOUR website! express sec 285 as a function of a positive acute angle whose measure is less than 45
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285 is in the 4th Quadrant where the secant is positive.
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The reference angle for 285 is 360-285 = 75 degrees
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sec(285) = sec(75) = csc(90-75) = csc(15)
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Cheers,
Stan H.