Post

Created by @nathanedwards
 at November 1st 2023, 4:20:52 am.

AP Calculus AB Exam Question:

Evaluate the following limit:

limx2x24x2\lim_{x \to 2} \frac{x^2 - 4}{x - 2}

Answer:

To evaluate the limit limx2x24x2\lim_{x \to 2} \frac{x^2 - 4}{x-2}, we need to see what happens as xx approaches 2 from both the left and right sides.

Step 1:

First, let's substitute x=2x = 2 directly into the expression:

22422\frac{2^2 - 4}{2-2}

We encounter an indeterminate form, since we have 0 in the denominator. Therefore, we need to utilize different techniques to evaluate the limit.

Step 2:

One way to proceed is to factor the numerator:

limx2(x2)(x+2)x2\lim_{x \to 2} \frac{(x-2)(x+2)}{x-2}

Step 3:

Now, we can cancel out the common factor of (x2)(x-2):

limx2(x+2)\lim_{x \to 2} (x+2)

Step 4:

Since there are no more indeterminate forms or discontinuities, we can evaluate the limit by simply substituting x=2x=2 into the expression:

2+2=42 + 2 = 4

Therefore, limx2x24x2=4\lim_{x \to 2} \frac{x^2 - 4}{x-2} = 4.