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Evaluate the limit, if it exists. (If an answer does not exist, enter DNE.) lim h → 0 (x + h)^3 − x^3/ h

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Final answer:

To evaluate the given limit, we can use the binomial theorem to expand the expression and then simplify it. The final answer is 3x^2.

Step-by-step explanation:

To evaluate the limit lim (h → 0) [(x + h)^3 - x^3] / h, we can apply the binomial theorem and simplify the expression. The binomial theorem states that (a + b)^3 = a^3 + 3a^2b + 3ab^2 + b^3. Using this, we can expand (x + h)^3 as x^3 + 3x^2h + 3xh^2 + h^3. Now, substitute the expanded expression back into the limit expression:

[(x + h)^3 - x^3] / h = (x^3 + 3x^2h + 3xh^2 + h^3 - x^3) / h = (3x^2h + 3xh^2 + h^3) / h = 3x^2 + 3xh + h^2. As h approaches 0, the term 3xh approaches 0 and the term h^2 approaches 0. Therefore, the limit is equal to 3x^2. So, the final answer is lim (h → 0) [(x + h)^3 - x^3] / h = 3x^2.

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