Question 831580
Find all valves k so that the natural domain of the following function is all real numbers. 
h(x)= (t-1)/(t^2+kt+4)
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Comment: The denominator must have NO Real Number roots.
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b^2-4ac must be negative.
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Solve: k^2 - 4*1*4 < 0
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k^2-16 < 0
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(k-4)(k+4) < 0
Solution: -4 < k < 4
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Cheers,
Stan H.
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