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Using a scientific calculator
Using a scientific calculator

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6.1 Using roots on your calculator

Just as there are keys on your calculator for entering powers, roots can also be entered directly. Square roots can be calculated using the key. For example, can be entered using . Cube roots are entered using the second function of this key. For higher roots, such as fourth or fifth roots you need to use the more general template, which is the second function of the key. This template is filled in by using the number and arrow keys (and ) in a way similar to that used when the fraction template is completed.

Activity 15 Calculating roots

Calculate each of the following using your calculator, giving your answer correct to 3 significant figures.


  1. (to 3 significant figures) using the key sequence .
  2. (to 3 significant figures) using the key sequence .
  3. (to 3 significant figures) using the key sequence .
  4. or 18.4 (to 3 significant figures) using the key sequence (and using to find the decimal result).

You will notice from the result of Activity 15, part 4 that the calculator sometimes presents answers using surds.

This is true only if the calculator is in the recommended Math mode.

To find the decimal equivalent of an answer like this, you can use the or keys that you used earlier to find the decimal forms of fractional answers.