9514 1404 393
Answer:
- a) 7
- b) -27
- c) 18
- d) 8
- e) 2
- f) 1
Step-by-step explanation:
The limit of any polynomial function at a point is the value of the polynomial at that point. A polynomial is defined and continuous for all values of the independent variable.
The limit of a rational function at a "hole" is the value of the simplified function at that point.
1a) lim = 4+3+2-2 = 7
1b) lim = (3)(-3)(3) = -27
1c) lim = 3^2+9 = 18
1d) lim = (x+4) = 4+4 = 8
1e) lim = 3x+1 = 3(1/3) +1 = 2
1f) lim = x^2/x^2 = 1
_____
The expressions of (e) and (f) can be simplified by factoring the difference of squares: a^2 -b^2 = (a -b)(a +b). In each case, one of the factors cancels the one in the denominator, so the remaining function can be evaluated at the limit point.
As x approaches infinity, the only terms of a rational expression that matter are those of the highest degree in numerator and denominator. (There's a little more to it if the numerator has a higher degree than the denominator.)
