Math Problem Statement

determine the equation of the tangent line of the function sqrt(x) at x=2

Solution

To find the equation of the tangent line to the function f(x)=xf(x) = \sqrt{x} at x=2x = 2, we follow these steps:

Step 1: Compute the derivative of f(x)f(x)

The derivative of f(x)=xf(x) = \sqrt{x} can be computed using the power rule. Rewriting x\sqrt{x} as x1/2x^{1/2}, we get:

f(x)=ddx(x1/2)=12x1/2=12xf'(x) = \frac{d}{dx} \left( x^{1/2} \right) = \frac{1}{2} x^{-1/2} = \frac{1}{2\sqrt{x}}

Step 2: Find the slope of the tangent line at x=2x = 2

The slope of the tangent line is given by the value of the derivative at x=2x = 2:

f(2)=122=121.4140.353f'(2) = \frac{1}{2\sqrt{2}} = \frac{1}{2\cdot 1.414} \approx 0.353

Step 3: Find the point on the curve at x=2x = 2

The point on the curve at x=2x = 2 is f(2)=21.414f(2) = \sqrt{2} \approx 1.414. So the point is (2,1.414)(2, 1.414).

Step 4: Use the point-slope form of the equation of a line

The point-slope form of a line is given by:

yy1=m(xx1)y - y_1 = m(x - x_1)

Where:

  • mm is the slope of the tangent line,
  • (x1,y1)(x_1, y_1) is the point of tangency.

Substitute m=0.353m = 0.353, x1=2x_1 = 2, and y1=1.414y_1 = 1.414:

y1.414=0.353(x2)y - 1.414 = 0.353(x - 2)

Step 5: Simplify the equation

Now, distribute and simplify:

y1.414=0.353x0.706y - 1.414 = 0.353x - 0.706

y=0.353x+0.708y = 0.353x + 0.708

Thus, the equation of the tangent line to f(x)=xf(x) = \sqrt{x} at x=2x = 2 is approximately:

y=0.353x+0.708y = 0.353x + 0.708

Summary

The equation of the tangent line is y=0.353x+0.708y = 0.353x + 0.708.

Would you like further details or have any questions?

Here are 5 related questions:

  1. How is the derivative of a square root function generally computed?
  2. What is the geometric interpretation of a tangent line?
  3. How can the point-slope form of a line be derived?
  4. What are other methods to find the equation of a tangent line?
  5. Can we use the same process for functions that involve trigonometric or exponential terms?

Tip: The derivative of x\sqrt{x} can always be expressed as 12x\frac{1}{2\sqrt{x}}, which is helpful for finding slopes of tangent lines for square root functions.

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Tangent Lines

Formulas

Derivative of sqrt(x) = 1 / (2 * sqrt(x))
Point-slope form: y - y1 = m(x - x1)

Theorems

Power Rule of Derivatives
Slope of a Tangent Line

Suitable Grade Level

Grades 11-12, College