Answer:
[tex]\displaystyle y - \frac{\sqrt{35}}{35} = \frac{-\sqrt{35}}{350}(x - 5)[/tex]
General Formulas and Concepts:
Pre-Algebra
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Algebra I
Coordinates (x, y)
Point-Slope Form: y - y₁ = m(x - x₁)
- x₁ - x coordinate
- y₁ - y coordinate
- m - slope
Algebra II
- Exponential Rule [Rewrite]: [tex]\displaystyle b^{-m} = \frac{1}{b^m}[/tex]
Calculus
Derivatives
- The definition of a derivative is the slope of the tangent line.
Derivative Notation
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
[tex]\displaystyle y = \frac{1}{\sqrt{7x}} \\x = 5[/tex]
Step 2: Differentiate
- [Function] Rewrite: [tex]\displaystyle y = \frac{1}{(7x)^\frac{1}{2}}[/tex]
- [Function] Rewrite [Exponential Rule - Rewrite]: [tex]\displaystyle y = (7x)^{-\frac{1}{2}}[/tex]
- [Derivative] Chain Rule [Function]: [tex]\displaystyle y' = \frac{-1}{2}(7x)^{-\frac{1}{2} - 1} \cdot \frac{d}{dx}[7x][/tex]
- [Derivative] Simplify: [tex]\displaystyle y' = \frac{-1}{2}(7x)^{-\frac{3}{2}} \cdot \frac{d}{dx}[7x][/tex]
- [Derivative] Basic Power Rule: [tex]\displaystyle y' = \frac{-1}{2}(7x)^{-\frac{3}{2}} \cdot 1 \cdot 7x^{1 - 1}[/tex]
- [Derivative] Simplify: [tex]\displaystyle y' = \frac{-7}{2}(7x)^{-\frac{3}{2}}[/tex]
- [Derivative] Rewrite [Exponential Rule - Rewrite]: [tex]\displaystyle y' = \frac{-7}{2(7x)^{\frac{3}{2}}}[/tex]
Step 3: Find Slope of Tangent Line
- Substitute in x [Derivative]: [tex]\displaystyle y'(5) = \frac{-7}{2[7(5)]^{\frac{3}{2}}}[/tex]
- [Tangent Slope] [Brackets] Multiply: [tex]\displaystyle y'(5) = \frac{-7}{2[35]^{\frac{3}{2}}}[/tex]
- [Tangent Slope] Evaluate exponents: [tex]\displaystyle y'(5) = \frac{-7}{2(35\sqrt{35})}[/tex]
- [Tangent Slope] Multiply: [tex]\displaystyle y'(5) = \frac{-7}{70\sqrt{35}}[/tex]
- [Tangent Slope] Simplify: [tex]\displaystyle y'(5) = \frac{-1}{10\sqrt{35}}[/tex]
- [Tangent Slope] Rationalize: [tex]\displaystyle y'(5) = \frac{-\sqrt{35}}{350}[/tex]
Step 4: Find Tangent Line Equation
Point (x, y)
- Substitute in x [Function]: [tex]\displaystyle y(5) = \frac{1}{\sqrt{7(5)}}[/tex]
- [Function] [√Radical] Multiply: [tex]\displaystyle y(5) = \frac{1}{\sqrt{35}}[/tex]
- [Function] Rationalize: [tex]\displaystyle y(5) = \frac{\sqrt{35}}{35}[/tex]
- Define point: [tex]\displaystyle (5, \frac{\sqrt{35}}{35})[/tex]
Equation
- Substitute in variables [Point-Slope Form]: [tex]\displaystyle y - \frac{\sqrt{35}}{35} = \frac{-\sqrt{35}}{350}(x - 5)[/tex]
Topic: AP Calculus AB/BC
Unit: Derivatives
Book: College Calculus 10e