Math Problem Statement

Solve the problem and return an answer choice

The graphs of the functions f and g are shown above. If h(x) = \frac{f(x)+4}{g(x)+2x}, then h'(3) =

Solution

We are given the graphs of two functions f(x)f(x) and g(x)g(x), and the function h(x)=f(x)+4g(x)+2xh(x) = \frac{f(x) + 4}{g(x) + 2x}. We are asked to find h(3)h'(3), the derivative of h(x)h(x) at x=3x = 3.

Step 1: Differentiate h(x)h(x)

We will use the quotient rule to differentiate h(x)h(x). The quotient rule states that for a function of the form u(x)v(x)\frac{u(x)}{v(x)}, the derivative is given by: h(x)=u(x)v(x)u(x)v(x)(v(x))2h'(x) = \frac{u'(x)v(x) - u(x)v'(x)}{(v(x))^2} In this case, u(x)=f(x)+4u(x) = f(x) + 4 and v(x)=g(x)+2xv(x) = g(x) + 2x.

Now, let's find the derivatives:

  • u(x)=f(x)u'(x) = f'(x) because the derivative of the constant 4 is 0.
  • v(x)=g(x)+2v'(x) = g'(x) + 2 because the derivative of 2x2x is 2.

Thus, applying the quotient rule: h(x)=(f(x))(g(x)+2x)(f(x)+4)(g(x)+2)(g(x)+2x)2h'(x) = \frac{(f'(x))(g(x) + 2x) - (f(x) + 4)(g'(x) + 2)}{(g(x) + 2x)^2}

Step 2: Calculate values at x=3x = 3

We need to find the values of f(3)f(3), f(3)f'(3), g(3)g(3), and g(3)g'(3) using the graphs.

  • From the graph of f(x)f(x), we can see that f(3)=5f(3) = 5.

  • The slope of f(x)f(x) from x=2x = 2 to x=4x = 4 is: f(3)=f(4)f(2)42=342=12f'(3) = \frac{f(4) - f(2)}{4 - 2} = \frac{3 - 4}{2} = \frac{-1}{2}

  • From the graph of g(x)g(x), we observe that g(3)=5g(3) = 5.

  • The slope of g(x)g(x) from x=2x = 2 to x=4x = 4 is: g(3)=g(4)g(2)42=152=42=2g'(3) = \frac{g(4) - g(2)}{4 - 2} = \frac{1 - 5}{2} = \frac{-4}{2} = -2

Step 3: Plug values into the derivative formula

Now substitute x=3x = 3, along with the values we calculated, into the formula for h(x)h'(x): h(3)=(12)(5+6)(5+4)(2+2)(5+6)2h'(3) = \frac{\left( \frac{-1}{2} \right)(5 + 6) - (5 + 4)(-2 + 2)}{(5 + 6)^2} Simplifying the terms: h(3)=(12)(11)(9)(0)112=112121=112×121=11242h'(3) = \frac{\left( \frac{-1}{2} \right)(11) - (9)(0)}{11^2} = \frac{\frac{-11}{2}}{121} = \frac{-11}{2 \times 121} = \frac{-11}{242}

Thus: h(3)=122h'(3) = \frac{-1}{22}

This does not match the available answer choices. Upon review, let's check if there was an arithmetic mistake.

The correct differentiation

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Quotient Rule

Formulas

Quotient Rule: \frac{u'(x)v(x) - u(x)v'(x)}{(v(x))^2}

Theorems

Quotient Rule for Differentiation

Suitable Grade Level

Grades 11-12