Desmos Calculator: Use Previous Answer (ans) Feature
This interactive tool demonstrates how the ‘ans’ feature in the Desmos calculator works, allowing you to chain calculations together seamlessly by using the result of your previous computation.
Step 1: Initial Calculation
Enter the first number for your calculation.
Select the mathematical operation.
Enter the second number for your calculation.
Step 2: Use Previous Answer
This is the result from Step 1. It is automatically used as the first value in this step.
Select the next operation to perform using the previous answer.
Enter the number to operate on with the previous answer.
Results
Final Result of (ans [Operation] C):
Intermediate Values
Initial Calculation (A [Op] B): 0
Formula Used:
This section shows the final output after using the intermediate result (‘ans’) in a subsequent calculation, mirroring the workflow in Desmos.
Calculation Flow Visualization
What is the ‘desmos calculator use previous answer’ feature?
The ability to use a previous answer in the Desmos calculator is a core feature for performing multi-step calculations efficiently. In Desmos, this is handled by a special variable called ans. Whenever you compute an expression in the calculator, the result is automatically stored in the ans variable. You can then type “ans” or use the dedicated `ans` button on the keypad to insert that result into your next calculation line.
This feature is invaluable for students, engineers, and scientists who need to perform a sequence of operations where the output of one step is the input for the next. It eliminates the need to manually re-type long or precise decimal numbers, reducing errors and saving time. For example, you might calculate the area of a circle and then immediately use that area to calculate the volume of a cylinder. This is a fundamental concept for anyone looking to master the Desmos scientific calculator.
Formula and Explanation for Using Previous Answer
There isn’t a single “formula” for using the previous answer, but rather a procedural concept. The workflow can be described as follows:
- Step 1: Initial Calculation → Result 1
- Step 2:
ansis now equal to Result 1 - Step 3: New Calculation using
ans→ Result 2
Essentially, the “formula” for the second step is New Result = (ans) [Operation] [New Value]. The `ans` variable acts as a placeholder for the numerical outcome of the preceding expression line.
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Initial Value(s) | The number or numbers used in the first calculation. | Unitless (or context-dependent) | Any real number |
ans |
The stored result from the previous expression line. | Unitless (or context-dependent) | The numerical output of the last calculation |
| New Value | The number used in the operation with ans. |
Unitless (or context-dependent) | Any real number |
Practical Examples
Example 1: Solving a Two-Step Physics Problem
Imagine you need to find the final velocity (v) of an object and then use it to calculate its kinetic energy (KE).
- Inputs (Step 1): Initial velocity (u) = 10 m/s, acceleration (a) = 2 m/s², time (t) = 5 s. Calculate final velocity:
v = u + at. - Calculation (Step 1):
10 + 2 * 5= 20. The calculator displays 20. - `ans` Value:
ansis now 20. - Inputs (Step 2): Mass (m) = 3 kg. Calculate kinetic energy:
KE = 0.5 * m * v². In Desmos, you’d type0.5 * 3 * ans^2. - Results: The final result for kinetic energy would be
0.5 * 3 * 20^2= 600 Joules.
Example 2: Chaining Percentage Calculations
Suppose you start with a value and need to apply two successive percentage discounts.
- Inputs (Step 1): Original price = $500, first discount = 15%. Calculate the price after the first discount.
- Calculation (Step 1):
500 * (1 - 0.15)= 425. - `ans` Value:
ansis now 425. - Inputs (Step 2): A second discount of 10% is applied to the new price. In Desmos, you’d type
ans * (1 - 0.10). - Results: The final price is
425 * 0.90= $382.50. This demonstrates how to use the previous answer effectively, a key skill for both basic and graphing calculator tasks.
How to Use This ‘desmos calculator use previous answer’ Demonstrator
This calculator is designed to visually and interactively teach you the concept of the ans feature.
- Enter Initial Values: In “Step 1”, input your first two numbers and choose an operation.
- Calculate: Click the “Calculate” button.
- Observe the ‘ans’ field: Notice how the result from Step 1 automatically populates the “Previous Answer (ans)” field in “Step 2”. This simulates Desmos storing the result.
- Perform Second Calculation: In “Step 2”, choose a new operation and enter a third value. The calculation will use the value from the ‘ans’ field.
- Review Results: The “Results” section shows you the final result, the intermediate result (the first answer), and the formula used. The bar chart provides a visual comparison of all values in the workflow.
- Interpret Results: Since this is an abstract math calculator, all values are unitless. The goal is to understand the flow of information from one calculation step to the next. For more advanced applications, explore a 3D calculator.
Key Factors That Affect Using ‘ans’ in Desmos
- Order of Operations: The
ansvariable always holds the result of the *last successfully evaluated expression line*. If you have multiple lines, the bottom-most one determines the value ofans. - Error States: If your last calculation results in an error (e.g., division by zero), the value of
answill not update. It will retain the result from the last valid calculation. - Clearing Expressions: Deleting an expression line that set the `ans` value will cause `ans` to revert to the result of the now-last expression line.
- Function Definitions: Defining a function like
f(x) = x^2does not produce a numerical result, so it does not updateans. However, calling the function, e.g.,f(3), will updateansto 9. - Graphing vs. Calculating: In the graphing calculator, an equation like
y = 2x + 1defines a line but doesn’t produce a single numerical result, so it won’t update `ans`. A direct calculation like3+5will. - Sliders and Variables: Using sliders to define variables is a powerful feature. If your last expression depends on a slider, changing the slider will dynamically update the result, and therefore update the `ans` value in real-time. This is useful for exploring how changes in one variable affect a multi-step outcome. See our guide on the geometry calculator for more on this.
Frequently Asked Questions (FAQ)
- 1. How do I access the previous answer in Desmos?
- You can either type the letters “ans” directly into an expression line or press the `ans` button on the Desmos keypad.
- 2. Can I use the answer from three steps ago?
- No, the `ans` variable only stores the result from the immediately preceding calculation line. To use older results, you should assign them to a variable, for example,
my_result = 3+5. You can then use `my_result` in any later expression. - 3. What is the initial value of `ans` when I open the calculator?
- Initially, `ans` is 0. It only gets a new value after you complete your first calculation.
- 4. Does `ans` work in the Desmos graphing calculator too?
- Yes, the `ans` feature works in the scientific, four-function, and graphing calculators. However, in the graphing calculator, it only stores results from expressions that yield a single numerical value, not from equations that draw a graph.
- 5. Do I have to do anything to store the previous answer?
- No, Desmos does it automatically. The result of every valid calculation is placed into the `ans` variable without any user action required.
- 6. How can I see the current value of `ans`?
- Simply type `ans` into a new expression line. The calculator will display its current numerical value.
- 7. Can I use `ans` inside a function definition?
- Yes, but it’s often not recommended as it can be confusing. The value of `ans` would be whatever it was when the function was called, not when it was defined. It is better practice to pass values as arguments, e.g.,
f(x) = x + 5instead off() = ans + 5. - 8. Is `ans` case-sensitive?
- Yes. You must use the lowercase “ans”. “Ans” or “ANS” will be treated as new, undefined variables.