Table of contents
- 0. Functions7h 52m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms34m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
- 8. Definite Integrals3h 25m
5. Graphical Applications of Derivatives
Curve Sketching
Problem 4.4.78c
Textbook Question
{Use of Tech} Elliptic curves The equation y² = x³ - ax + 3, where a is a parameter, defines a well-known family of elliptic curves.
c. By experimentation, determine the approximate value of a (3 < a < 4)at which the graph separates into two curves.

1
Understand the problem: We are dealing with a family of elliptic curves defined by the equation y² = x³ - ax + 3, where 'a' is a parameter. Our goal is to find the approximate value of 'a' between 3 and 4 where the graph separates into two distinct curves.
Consider the discriminant of the cubic polynomial x³ - ax + 3. The discriminant will help us determine when the cubic has a double root, which is a key point where the nature of the graph changes.
Calculate the discriminant of the cubic polynomial x³ - ax + 3. The discriminant Δ of a cubic equation x³ + bx + c is given by Δ = -4b³ - 27c². In our case, b = -a and c = 3.
Set the discriminant equal to zero to find the critical value of 'a'. This is because a zero discriminant indicates a double root, which is where the graph changes from a single connected curve to two separate curves.
Solve the equation -4(-a)³ - 27(3)² = 0 for 'a'. This will give you the critical value of 'a' where the graph separates. Since we are looking for an approximate value between 3 and 4, ensure that the solution falls within this range.
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