Solving a system of equations
Task
Find a polynomial function of degree 3 having a stationary inflection point at (1, 1) and passing through point (2, 2).
Instructions
| 1. | | In the Input Bar, define the function f(x):= a x^3 + b x^2 + c x + d. |
| 2. | p | According to the task, the function value at x=1 is 1. Enter p: f(1) = 1;
and press the Enter key.
Hints: The input ":" names your equation, while the semicolon “;” suppresses the output. |
| 3. | q | We also know that the function value at x=2 is 2. Enter q: f(2) = 2;
into the Input Bar.
|
| 4. | r | Since (1, 1) is an inflection point, the first derivative equals 0 at x=1. Enter r: f'(1) = 0;
Hint: The derivative of f can be written as f'. |
| 5. | s | We also know that the second derivative equals 0 at x=1. Enter s: f''(1) = 0;
|
| 6. | ![]() | Select rows two through five and apply the Solve tool. |
| | | Hints:
|
| 7. | Substitute | Enter Substitute($1, $6) into the Input Bar and press the Enter key.
Note: You just substituted the undefined variables in the formula of f ($1) with the solutions you just calculated ($6). |
| 8. | | Activate the disabled Visibility button below row number 7 to plot the function in the |
