lim h -> 0 ?

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1 Answer
Cesareo R.
Jan 15, 2017

9

Explanation:

f(x)=abs(-9x-7)=abs(9x+7)

(f(6+h)-f(6))/h=(abs(9(6+h)+7)-abs(9xx6+7))/h=
(abs(61+9h)-61)/h = 9((abs(61/9+h)-61/9)/h)

now

a) if h > 0->abs(61/9+h)=61/9+h so
9((abs(61/9+h)-61/9)/h)=9(61/9+h-61/9)/h=9

b) if h < 0->abs(61/9-h)=61/9-h so
9((abs(61/9+h)-61/9)/h)=9(61/9-h-61/9)/(-h)=9

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