if you a function such as f(x)= (x^2+4x-12)/(x^2-2x) if you wanna find lim x-2, you do f(2) is that right

Question

if you a function such as f(x)= (x^2+4x-12)/(x^2-2x)  if you wanna find lim x->2, you do f(2) is that right

anonymous · Answer

is this because limx->a(fx)=f(a) ??

calculusfunctions · Answer

NO!!!!!!!!!!!!!!

calculusfunctions · Answer

TO FIND A LIMIT OF A FUNCTION IS NOT THE SAME AS FINDING WHERE THE FUNCTION IS DISCONTINUOUS!!!!!

anonymous · Answer

im not finding discontinuous?? i wanna find the lim x->2

calculusfunctions · Answer

Yes I know, that is exactly what I have been trying to tell you since you've been messaging me! In the  messages I already told you that since it is an indeterminate form of a rational function, you first simplify the rational function and then evaluate the limit.

anonymous · Answer

so if u get a indeterminate form you simplify and do f(a)

anonymous · Answer

@calculusfunctions  WILL YOU HAVE TIME TO HELP ME WITH 2 QUESTIONS when ur done here

calculusfunctions · Answer

Example:$$\lim_{x \rightarrow -2}\frac{ 4-x ^{2} }{ 2+x }$$If you substitute x = -2 into this rational function, you'll find that  f(-2) = 0/0.  Thus this limit is an indeterminate form.  Hence we will first simplify the rational function by factoring both the numerator and the denominator as much and if possible, then divide any like factors. Thus$$\lim_{x \rightarrow -2}\frac{ 4-x ^{2} }{ 2+x }$$
$$=\lim_{x \rightarrow -2}\frac{ (2-x)(2+x) }{ 2+x }$$
$$=\lim_{x \rightarrow -2}(2-x)$$
$$=2-(-2)$$
$$=4$$Therefore$$\lim_{x \rightarrow -2}\frac{ 4-x ^{2} }{ 2+x }=4$$

anonymous · Answer

fanks teacher.  line after limx->-2(2-x) you subbed x=-2 right. why is that a valid step? 
is that because limx->af(x)=f(a)?