Question

Cum rezolv: lim X-> 3 din X la 2 -4x-3 totul supra x la2 - 9?

Answer 1

daca la numarator este -3, inlocuind x cu 3 se obtine -6 supra 0 cu plus sau minus, si avam limite laterale infinite

Answer 2

$\lim_{x \to \ 3 \frac{x^2-4x+3}{x^2-9}$


[tex]x^2-4x+3=0 a=1 b=-4 c=3 delta=b^2-4ac = (-4)^2-4*3=16-12=4[/tex]

$x1= \frac{4+2}{2}= \frac{6}{2}=3$

$x2= \frac{4-2}{2}= \frac{2}{2}=1$

Conform formulei a(x-x1)(x-x2)=(x-3)(x-1)

x^2-9=(x-3)(x+3)

$\lim_{x \to \ 3 \frac{(x-3)(x-1)}{(x-3)(x+3)}= \frac{2}{6}= \frac{1}{3}$