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Simplifique [f(x + h) - f(x)] / h sendo f(x) = x²-2x

Rafaela

- Matemática

Simplifique [f(x + h) - f(x)] / h sendo f(x) = x²-2x

1 Resposta

XXXTh

oxed{oxed{ frac{f(x+h)-f(x)}{h} }}

a)  lembrando algumas propriedades : 
matrix (apm b)^2=a^2pm2ab+b^2\\(a^2b^2)= (ab)^2\\ a^2-b^2=(a+b)(a-b)\\ frac{a}{b}pm frac{c}{d}= frac{adpm cb}{bd} end

f(x+h) -> substitui o x da função por x+h

temos:
frac{ frac{1}{(x+h)^2} - frac{1}{x^2} }{h} \\ = left(  frac{1}{(x+h)^2} - frac{1}{x^2}
ight)  frac{1}{h} \\ =  left(   frac{x^2-(x+h)^2}{(x+h)^2x^2}
ight)  frac{1}{h} \\ = left(   frac{[x+(x+h)] [(x-(x+h)]}{(x+h)^2x^2}
ight)  frac{1}{h} \\ = left(   frac{(2x+h)(-h)}{(x+h)^2x^2}
ight)  frac{1}{h} \\ = left(   frac{(2x+h)(-
ot h)}{(x+h)^2x^2}
ight)  frac{1}{
ot h}  \\ =  frac{(2x+h)(-1)}{(x+h)^2x^2} \\ =  frac{-(2x+h)}{[x(x+h)]^2}

b)

f(x)= frac{1}{(x+2)} \\:::::::::::::::::::::::::::::: \\ frac{ frac{1}{x+h+2}- frac{1}{x+2} }{h} =\\ = left( frac{1}{x+h+2} - frac{1}{x+2} 
ight) frac{1}{h} \\ = left( frac{(x+2)-(x+h+2)}{(x+h+2)(x+2)} 
ight) frac{1}{h} \\ = left( frac{x+2-x-h-2}{(x+h+2)(x+2)} 
ight) frac{1}{h} \\ = left( frac{- 
ot h}{(x+h+2)(x+2)} 
ight) frac{1}{
ot h} \\ = frac{-1}{(x+2)(x+h+2)}

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