Identify Function and Point: Identify the function and the point at which we need to find the limit. The function is (x3−4x2)/(x2−16) and we need to find the limit as x approaches 4.
Attempt Direct Substitution: Attempt to directly substitute x=4 into the function to see if the limit can be evaluated this way.Substitute x=4 into (x3−4x2)/(x2−16) to check if the function is defined at this point.((4)3−4(4)2)/((4)2−16)=(64−64)/(16−16)=0/0We get an indeterminate form 0/0, which means we cannot directly evaluate the limit by substitution.
Factor and Simplify Expression: Factor the numerator and denominator to simplify the expression and potentially cancel out common factors.The numerator x3−4x2 can be factored as x2(x−4).The denominator x2−16 can be factored as (x+4)(x−4).Now the function is (x2(x−4))/((x+4)(x−4)).
Cancel Common Factor: Cancel out the common factor (x−4) from the numerator and denominator.After canceling, the function simplifies to (x+4)x2.
Evaluate Limit: Now that the function is simplified, try to directly substitute x=4 again.Substitute x=4 into x+4x2 to evaluate the limit.4+4(4)2=816=2The limit as x approaches 4 is 2.