Evaluate the limit, if it exists.

lim x->-4 (x+4)/(x^3 + 64)

1 answer

To evaluate the limit as x approaches -4, we substitute -4 into the expression:

lim x->-4 (x+4)/(x^3 + 64) = (-4 + 4)/((-4)^3 + 64) = 0/(64 - 64) = 0/0

Since we get 0/0, this is an indeterminate form. To further evaluate the limit, we can factor the denominator:

lim x->-4 (x+4)/(x^3 + 64) = (x+4)/((x+4)(x^2 - 4x + 16))

We can cancel out the common factor of (x+4):

lim x->-4 1/(x^2 - 4x + 16)

Now we can substitute -4 into the expression:

lim x->-4 1/((-4)^2 - 4(-4) + 16) = 1/(16 + 16 + 16) = 1/48

Therefore, the limit of the expression as x approaches -4 is 1/48.