Math Problem Statement

Let H(x) = 4f(x) + g(x), where the graphs of f and g are shown in the figure to the right. Find H'(1).

Solution

To find H(1)H'(1) given that H(x)=4f(x)+g(x)H(x) = 4f(x) + g(x), we need to differentiate H(x)H(x):

H(x)=4f(x)+g(x)H'(x) = 4f'(x) + g'(x)

We then substitute x=1x = 1:

H(1)=4f(1)+g(1)H'(1) = 4f'(1) + g'(1)

Now, we need to find the derivatives f(1)f'(1) and g(1)g'(1) using the graphs of f(x)f(x) and g(x)g(x).

Step 1: Find f(1)f'(1)

From the graph, the function f(x)f(x) is a straight line (blue line), so its slope is constant. The slope can be found as:

f(x)=ΔyΔx=4040=1f'(x) = \frac{\Delta y}{\Delta x} = \frac{4 - 0}{4 - 0} = 1

Thus, f(1)=1f'(1) = 1.

Step 2: Find g(1)g'(1)

Similarly, for g(x)g(x) (red line), its slope is also constant:

g(x)=ΔyΔx=01040=104=2.5g'(x) = \frac{\Delta y}{\Delta x} = \frac{0 - 10}{4 - 0} = -\frac{10}{4} = -2.5

Thus, g(1)=2.5g'(1) = -2.5.

Step 3: Substitute into the derivative of H(x)H(x)

H(1)=41+(2.5)=42.5=1.5H'(1) = 4 \cdot 1 + (-2.5) = 4 - 2.5 = 1.5

Final Answer:

H(1)=1.5H'(1) = 1.5

Would you like further details or have any questions? Here are some related questions to explore:

  1. How do you differentiate a linear combination of functions?
  2. How do you find the slope of a line from a graph?
  3. What is the significance of the derivative in understanding the rate of change?
  4. Can we find the second derivative H(x)H''(x) using the given functions?
  5. What are other real-life applications of derivatives in problem-solving?

Tip: When dealing with graphs of functions, always look for consistent patterns in slope to simplify derivative calculations!

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation

Formulas

Derivative of a sum: (f(x) + g(x))' = f'(x) + g'(x)
Constant multiplication rule: (cf(x))' = c * f'(x)

Theorems

Linearity of Derivatives
Power Rule

Suitable Grade Level

College or Advanced High School (AP Calculus)