Math Problem Statement

Find the slope and an equation of the line tangent to the graph of

f(x)=e^x+3/e^x at x=0 .

    Slope of the tangent line:   m=

Number

    An equation of the tangent line: 

Solution

To find the slope and the equation of the tangent line to the graph of f(x)=ex+3exf(x) = e^x + \frac{3}{e^x} at x=0x = 0, we need to follow these steps:

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

The slope of the tangent line at a point xx on the graph is given by the derivative f(x)f'(x) evaluated at that point.

The function is: f(x)=ex+3exf(x) = e^x + \frac{3}{e^x}

The derivative f(x)f'(x) is calculated by differentiating each term:

  1. The derivative of exe^x is exe^x.
  2. The derivative of 3ex=3ex\frac{3}{e^x} = 3 \cdot e^{-x} is 3ex-3e^{-x}.

So, f(x)=ex3exf'(x) = e^x - \frac{3}{e^x}

Step 2: Evaluate f(0)f'(0) for the slope mm

Now, substitute x=0x = 0 into f(x)f'(x) to find the slope of the tangent line: f(0)=e03e0=13=2f'(0) = e^0 - \frac{3}{e^0} = 1 - 3 = -2

Thus, the slope of the tangent line is: m=2m = -2

Step 3: Find the equation of the tangent line

To write the equation of the tangent line, we use the point-slope form: yf(0)=m(x0)y - f(0) = m(x - 0)

First, calculate f(0)f(0): f(0)=e0+3e0=1+3=4f(0) = e^0 + \frac{3}{e^0} = 1 + 3 = 4

So, the point at x=0x = 0 is (0,4)(0, 4), and we have the slope m=2m = -2.

Using the point-slope form: y4=2(x0)y - 4 = -2(x - 0) which simplifies to: y=2x+4y = -2x + 4

Final Answer

  • Slope of the tangent line: m=2m = -2
  • Equation of the tangent line: y=2x+4y = -2x + 4

Would you like further details or have any questions?

Here are some related questions to deepen understanding:

  1. How would the tangent line change if the function were f(x)=ex3exf(x) = e^x - \frac{3}{e^x} instead?
  2. What is the significance of finding the tangent line at a specific point?
  3. How does the exponential function affect the shape and slope of the graph?
  4. How would you find the second derivative f(x)f''(x) to analyze concavity?
  5. What happens to the tangent line equation if we evaluate it at a different point, like x=1x = 1?

Tip: For exponential functions, remember that derivatives can often involve both positive and negative exponents, reflecting growth and decay in different directions.

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Tangent Lines
Exponential Functions

Formulas

Derivative of f(x) = e^x + 3/e^x: f'(x) = e^x - 3/e^x
Point-slope form of a line: y - y1 = m(x - x1)

Theorems

Definition of Derivative
Properties of Exponential Functions

Suitable Grade Level

Grades 11-12