Advanced Indices

Maths: Edexcel IGCSE Higher, topic 1.4.4

Advanced Powers and Roots

Powers and roots can be expressed (written) in more than one way.

Negative powers

Negative powers

  • Negative powers are equivalent (the same as) to 1 ÷ the number.
Half powers

Half powers

  • Half powers are the same as a square root.
Third powers

Third powers

  • Third powers are the same as cube roots.
Fraction powers

Fraction powers

  • Deal with one part of the fraction at a time.

Calculating Fractional Powers

Fractions can be powers.

Step 1 with a positive fractional power

Step 1 with a positive fractional power

  • The denominator of the fractional power becomes the root of the number.
  • The numerator of the fractional power becomes the power of the number.
Step 2 with a positive fractional power

Step 2 with a positive fractional power

  • Calculate the root of the number first.
Step 3 with a positive fractional power

Step 3 with a positive fractional power

  • Calculate the power of the answer to the previous step.
Step 1 with a negative fractional power

Step 1 with a negative fractional power

  • Go through the same process as with a positive fractional power.
  • But, it is now equivalent (the same as) to 1 ÷ the number.
Step 2 with a negative fractional power

Step 2 with a negative fractional power

  • Calculate the answer to the positive fractional power.
  • Insert the answer as the denominator to a fraction. The numerator is 1.
  • The answer can either remain as a fraction or you can convert it into a decimal.

Test yourself on Advanced Indices

  • What is an equivalent way of writing the power shown in the image?

  • What is an equivalent way of writing the power shown in the image?

  • What is an equivalent way of writing the power shown in the image?

  • What is an equivalent way of writing the power shown in the image?

  • What is an equivalent way of writing the power shown in the image?

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