06.08.2013 Views

Web skærmformat. - Aarhus Universitet

Web skærmformat. - Aarhus Universitet

Web skærmformat. - Aarhus Universitet

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

III. Potensrækker – 1. l’Hospitals regel og uegentlige integraler 252<br />

1.6. Overbevis ☞ [S] 4.5 Indeterminate forms and l’Hospital’s rule<br />

Bevis<br />

Fra den udvidede middelværdisætning<br />

Beregn nu<br />

f(x)g ′ (x ∗ ) = f ′ (x ∗ )g(x), a < x ∗ < x<br />

f(x) f<br />

lim = lim<br />

x→a g(x) x→a<br />

′ (x∗ )<br />

g ′ (x∗ f<br />

= lim<br />

) x→a<br />

′ (x)<br />

g ′ (x)<br />

1.7. Prøv reglen ☞ [S] 4.5 Indeterminate forms and l’Hospital’s rule<br />

Eksempel<br />

ubestemt af form 0<br />

0 .<br />

Heraf fås<br />

x<br />

lim<br />

x→1<br />

2 − 1<br />

x − 1<br />

f(x) = x 2 − 1,f ′ (x) = 2x<br />

g(x) = x − 1,g ′ (x) = 1<br />

x<br />

lim<br />

x→1<br />

2 − 1 2x<br />

= lim = 2<br />

x − 1 x→1 1

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!