Q. Determine whether the function f(x) is continuous at x=4.f(x)={11−2x2,−16−x,x≤4x>4f(x) is discontinuous at x=4f(x) is continuous at x=4
Check Conditions: To determine if the function f(x) is continuous at x=4, we need to check if the following three conditions are met:1. f(4) is defined.2. The limit of f(x) as x approaches 4 from the left side (limx→4−f(x)) equals the limit of f(x) as x approaches 4 from the right side (x=40).3. Both of these limits equal f(4).
Find f(4): First, we find f(4) using the piece of the function defined for x≤4, which is f(x)=11−2x2. Substitute x=4 into this piece to get f(4)=11−2(4)2=11−32=−21.
Find limx→4−f(x): Next, we find the limit of f(x) as x approaches 4 from the left side (limx→4−f(x)).Since the function for x≤4 is f(x)=11−2x2, the limit as x approaches 4 from the left is the same as f(4), which is f(x)0.
Find limx→4+f(x): Now, we find the limit of f(x) as x approaches 4 from the right side (limx→4+f(x)).For x > 4, the function is defined as f(x)=−16−x. We substitute x=4 into this piece to find the limit as x approaches 4 from the right, which gives us f(x)0.
Compare Limits: We compare the two one-sided limits and the value of f(4). From the left, the limit is −21, and from the right, the limit is −20. Since these two limits are not equal, the function is not continuous at x=4.