Math Problem Statement

Suppose that f and g are continuous functions such that f(5) = 8 and lim[x->5](f(x) + 5g(x)) = 17. Then we can calculate that (a) lim[x->5] f(x) = ? (b) lim[x->5] g(x) = ? (c) g(5) = ?

Solution

Let's analyze the problem step by step.

We are given:

  • f(5)=8f(5) = 8
  • limx5[f(x)+5g(x)]=17\lim_{x \to 5} \left[ f(x) + 5g(x) \right] = 17

The problem asks us to find the following limits and function values: (a) limx5f(x)\lim_{x \to 5} f(x) (b) limx5g(x)\lim_{x \to 5} g(x) (c) g(5)g(5)

Step 1: Analyzing f(x)f(x)

Since f(x)f(x) is continuous, the value of the function at a point is equal to the limit at that point. Therefore: limx5f(x)=f(5)=8\lim_{x \to 5} f(x) = f(5) = 8 Thus, the answer to part (a) is: 8\boxed{8}

Step 2: Analyzing g(x)g(x)

Next, we know from the given equation that: limx5[f(x)+5g(x)]=17\lim_{x \to 5} \left[ f(x) + 5g(x) \right] = 17 Substituting limx5f(x)=8\lim_{x \to 5} f(x) = 8, we have: 8+5limx5g(x)=178 + 5 \lim_{x \to 5} g(x) = 17 Solving for limx5g(x)\lim_{x \to 5} g(x): 5limx5g(x)=178=95 \lim_{x \to 5} g(x) = 17 - 8 = 9 limx5g(x)=95\lim_{x \to 5} g(x) = \frac{9}{5} Thus, the answer to part (b) is: 95\boxed{\frac{9}{5}}

Step 3: Analyzing g(5)g(5)

Since g(x)g(x) is continuous, the limit and the function value at that point are equal. Therefore: g(5)=limx5g(x)=95g(5) = \lim_{x \to 5} g(x) = \frac{9}{5} Thus, the answer to part (c) is: 95\boxed{\frac{9}{5}}

Summary of answers:

(a) limx5f(x)=8\lim_{x \to 5} f(x) = 8
(b) limx5g(x)=95\lim_{x \to 5} g(x) = \frac{9}{5}
(c) g(5)=95g(5) = \frac{9}{5}


Would you like any more details or further clarification?

Here are 5 related questions to deepen your understanding:

  1. How do we know that f(x)f(x) and g(x)g(x) are continuous at x=5x = 5?
  2. What would change if f(x)f(x) were not continuous at x=5x = 5?
  3. Why do we solve for limx5g(x)\lim_{x \to 5} g(x) by isolating it from the equation?
  4. How would you find limx5[2f(x)3g(x)]\lim_{x \to 5} \left[ 2f(x) - 3g(x) \right] using the values we computed?
  5. Can you explain the importance of limits in calculus, particularly for continuous functions?

Tip: Continuity is crucial because it guarantees that the value of a function at a point equals the limit at that point, making it easier to calculate limits!

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Math Problem Analysis

Mathematical Concepts

Calculus
Limits
Continuity of Functions

Formulas

lim[x->c] f(x) = f(c) for continuous functions

Theorems

Limit Laws
Continuity Theorem

Suitable Grade Level

Grades 11-12 or Introductory College Level