Question 503229
f(x) = 5x^2 + 9
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f(a+h) = 5(a+h)^2+9
= 5[a^2+2ha+h^2]+9
= 5a^2+10ha+5h^2+9
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f(a) = 5a^2+9
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[f(a+h)-f(a)] = 10ha+5h^2
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[f(a+h)-f(a)]/h = 10a+5h
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Cheers,
Stan H.