Respuesta :
Answer:
[tex]\displaystyle f''(1) = \frac{7}{\sqrt{43}}[/tex]
General Formulas and Concepts:
Pre-Algebra
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
- Left to Right
Algebra I
Point-Slope Form: y - y₁ = m(x - x₁)
- x₁ - x coordinate
- y₁ - y coordinate
- m - slope
Calculus
Derivatives
Derivative Notation
Taking Derivatives with respect to x
Basic Power Rule:
- f(x) = cxⁿ
- f’(x) = c·nxⁿ⁻¹
Chain Rule: [tex]\displaystyle \frac{d}{dx}[f(g(x))] =f'(g(x)) \cdot g'(x)[/tex]
Step-by-step explanation:
Step 1: Define
Function: y = f(x), twice differentiable.
[tex]\displaystyle f(1) = 3\\\frac{dy}{dx} = (4y^2 + 7x^2)^{\frac{1}{2}}[/tex]
Step 2: Differentiate
Remember we are taking the derivative with respect to x.
- Chain Rule [Basic Power Rule]: [tex]\displaystyle \frac{d^2y}{dx^2} = \frac{1}{2}(4y^2 + 7x^2)^{\frac{1}{2} - 1} \cdot \frac{dy}{dx} (4y^2 + 7x^2)[/tex]
- [2nd Derivative] Simplify: [tex]\displaystyle \frac{d^2y}{dx^2} = \frac{1}{2}(4y^2 + 7x^2)^{-\frac{1}{2}} \cdot \frac{dy}{dx} (4y^2 + 7x^2)[/tex]
- [2nd Derivative - Chain Rule] Basic Power Rule: [tex]\displaystyle \frac{d^2y}{dx^2} = \frac{1}{2}(4y^2 + 7x^2)^{-\frac{1}{2}} \cdot (0 + 2 \cdot 7x^{2 - 1})[/tex]
- [2nd Derivative] Simplify: [tex]\displaystyle \frac{d^2y}{dx^2} = \frac{1}{2}(4y^2 + 7x^2)^{-\frac{1}{2}} \cdot 2 \cdot 7x[/tex]
- [2nd Derivative] Simplify: [tex]\displaystyle \frac{d^2y}{dx^2} = \frac{7x}{\sqrt{7x^2 + 4y^2}}[/tex]
Step 3: Evaluate
We are given x = 1 and f(1) = 3. This will tell us the instantaneous slope.
- Substitute [2nd Deriv]: [tex]\displaystyle f''(1) = \frac{7(1)}{\sqrt{7(1)^2 + 4(3)^2}}[/tex]
- [√Radical] Exponents: [tex]\displaystyle f''(1) = \frac{7(1)}{\sqrt{7(1) + 4(9)}}[/tex]
- [Fraction] Multiply: [tex]\displaystyle f''(1) = \frac{7}{\sqrt{7 + 36}}[/tex]
- [√Radical] Add: [tex]\displaystyle f''(1) = \frac{7}{\sqrt{43}}[/tex]
This tells us that the rate of change of the slope of the tangent line is [tex]\displaystyle \frac{7}{\sqrt{43}}[/tex].
We can also write an equation for the instantaneous slope:
[Equation] [tex]\displaystyle y - 3 = \frac{7}{\sqrt{43}}(x - 1)[/tex]