AP Calculus AB Exam Question:
Evaluate the following limit:
x→2limx−2x2−4Answer:
To evaluate the limit limx→2x−2x2−4, we need to see what happens as x approaches 2 from both the left and right sides.
Step 1:
First, let's substitute x=2 directly into the expression:
2−222−4We 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:
x→2limx−2(x−2)(x+2)Step 3:
Now, we can cancel out the common factor of (x−2):
x→2lim(x+2)Step 4:
Since there are no more indeterminate forms or discontinuities, we can evaluate the limit by simply substituting x=2 into the expression:
Therefore, limx→2x−2x2−4=4.