Math Problem Statement

Create a linearization for f(x) = ∛x centered at x = 8. Use this to approximate ∛7.75. Write the answer as an improper fraction in lowest terms. Express each derivative in differential form.

Solution

H1. Linearization of f(x)=x3f(x) = \sqrt[3]{x} at x=8x = 8

  1. Find f(x)f'(x): f(x)=x1/3f(x)=13x2/3=13x23f(x) = x^{1/3} \quad \Rightarrow \quad f'(x) = \frac{1}{3} x^{-2/3} = \frac{1}{3\sqrt[3]{x^2}}

  2. Calculate f(8)f(8) and f(8)f'(8): f(8)=83=2f(8) = \sqrt[3]{8} = 2 f(8)=13823=134=112f'(8) = \frac{1}{3 \sqrt[3]{8^2}} = \frac{1}{3 \cdot 4} = \frac{1}{12}

  3. Linearization at x=8x = 8: The linear approximation L(x)L(x) is given by: L(x)=f(8)+f(8)(x8)=2+112(x8)L(x) = f(8) + f'(8)(x - 8) = 2 + \frac{1}{12}(x - 8)

  4. Approximate 7.753\sqrt[3]{7.75}: L(7.75)=2+112(7.758)=2+112(0.25)=20.2512=2148L(7.75) = 2 + \frac{1}{12}(7.75 - 8) = 2 + \frac{1}{12}(-0.25) = 2 - \frac{0.25}{12} = 2 - \frac{1}{48} L(7.75)=9648148=9548L(7.75) = \frac{96}{48} - \frac{1}{48} = \frac{95}{48} So, the approximate value of 7.753\sqrt[3]{7.75} is 9548\frac{95}{48}.

H2. Derivatives in Differential Form

  1. y=tanh(x+4)y = \tanh(x + 4): dy=sech2(x+4)dxdy = \text{sech}^2(x + 4) \, dx

  2. w=ln(t73t)w = \ln(t^7 - 3t): dw=7t63t73tdtdw = \frac{7t^6 - 3}{t^7 - 3t} \, dt

  3. x=arctan(y3)x = \arctan(y^3): dx=3y21+y6dydx = \frac{3y^2}{1 + y^6} \, dy

  4. z=esecpz = e^{\sec p}: dz=esecpsecptanpdpdz = e^{\sec p} \sec p \tan p \, dp

Would you like any further details or explanations?

Here are some related questions you might find useful:

  1. How do we find the linearization of a different function, say f(x)=xf(x) = \sqrt{x}, at a given point?
  2. What is the geometric interpretation of the linear approximation?
  3. Can you explain how to find the derivative of more complex functions involving products or quotients?
  4. How can linearization be used in error estimation?
  5. What are some real-life applications of differential forms and linear approximations?

Tip: When approximating a function near a point, linearization can provide a very close estimate for small deviations from the center point.

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Math Problem Analysis

Mathematical Concepts

Linearization
Derivatives
Differential Calculus

Formulas

f'(x) = (1/3)x^(-2/3)
Linear approximation formula: L(x) = f(a) + f'(a)(x - a)
Derivative of hyperbolic tangent: dy = sech^2(u) du
Chain rule for logarithmic functions: dw = (7t^6 - 3)/(t^7 - 3t) dt
Derivative of arctangent: dx = 3y^2/(1 + y^6) dy
Derivative of exponential functions: dz = e^(sec(p)) sec(p) tan(p) dp

Theorems

Chain Rule
Linear Approximation Theorem

Suitable Grade Level

Grades 11-12, Early College Calculus