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06 Numbers and Powers

Power Function Calculator: Calculate x to the n

Card No. 06·12744 · Updated · Standard formula, shown below

The calculator on this card is switched off while it is checked. The formula is below, and the worked example shows how to do the sum by hand.

Use this power function calculator to evaluate a number raised to an exponent, written as xⁿ. Enter the base and exponent to get the result; for example, it calculates 2⁵ as 32 and can also handle fractional or negative exponents within the real-number rules described below.

Formula

The power function is f(x) = xⁿ. In this calculator, base is x, the number being raised to a power, and exp is n, the exponent. The output is base multiplied by itself exp times when exp is a positive integer.

For example, x⁴ means x × x × x × x. Exponents are dimensionless counts in the usual arithmetic sense, so the calculator’s inputs and output have no assigned physical unit. If the base represents a measured quantity, its unit is raised to the exponent as well: for instance, a length in metres squared becomes an area in square metres.

Worked Example

With the default inputs, base = 2 and exp = 5:

  1. Write the expression: 2⁵.
  2. Multiply five copies of 2: 2 × 2 × 2 × 2 × 2.
  3. Evaluate: 4 × 2 × 2 × 2 = 8 × 2 × 2 = 16 × 2 = 32.

The calculator returns 32, displayed to six decimal places as 32.000000.

What a Power Function Means

A power function describes how a fixed base changes when raised to a variable exponent, or how a fixed exponent transforms different bases. The notation xⁿ is also called exponentiation. The base and exponent play different roles: in 3², 3 is the base and 2 is the exponent; the answer is 9.

For a positive whole-number exponent, exponentiation is repeated multiplication. Other exponents follow consistent mathematical rules:

  • Exponent zero: x⁰ = 1 for every nonzero x.
  • Negative exponent: x⁻ⁿ = 1/xⁿ, provided x is not zero. For example, 2⁻³ = 1/8 = 0.125.
  • Fractional exponent: x^(1/n) represents an nth root when that root is real. For example, 9^(1/2) = √9 = 3.
  • Other rational exponents: x^(m/n) can be understood as an nth root followed by raising to m, subject to real-number restrictions.

How to Use the Calculator

  • Enter the number to be raised in the Base field.
  • Enter the power in the Exponent field. Use 2 for a square, 3 for a cube, or a negative or fractional value when appropriate.
  • Read the result as the base raised to the exponent. The result is rounded to six decimal places for display; this does not mean the underlying value is necessarily exact to that many decimal places.

For a scientific-notation value such as 4.2 × 10⁶, first evaluate the power of ten or use the calculator’s base input only if you have rewritten the entire expression correctly. For example, (4.2 × 10⁶)² is 4.2² × 10¹² = 17.64 × 10¹², not 4.2 × 10¹².

Examples and Reading the Result

Changing the exponent can produce very different results even when the base stays fixed. With base 3, exponent 2 gives 9, exponent 0 gives 1, and exponent −2 gives 1/9, or about 0.111111. With base 10, exponent 3 gives 1,000, while exponent 0.5 gives √10, approximately 3.162278.

A negative base needs particular care. A negative base raised to an integer exponent is real: (−2)³ = −8, while (−2)⁴ = 16. Parentheses matter. The expression −2⁴ is conventionally interpreted as −(2⁴), which equals −16, whereas (−2)⁴ equals 16.

Some fractional powers of negative bases have real values and others do not. For example, (−8)^(1/3) has the real value −2, because the cube root of −8 is −2. But (−8)^(1/2) has no real-number result; its square root is complex. Calculator software can differ in how it handles fractional powers of negative inputs, so verify the intended domain when a result is missing or unexpected.

Common Mistakes and Limits

  • Confusing the base and exponent: 2³ is 8, but 3² is 9. They are not interchangeable.
  • Leaving out parentheses: use parentheses to show that an entire negative number is the base, as in (−2)⁴.
  • Assuming every exponent means repeated multiplication: that description directly applies to positive integers. Roots and reciprocals explain fractional and negative exponents.
  • Rounding too early: keep full precision in intermediate steps when comparing or combining calculations, and round the final result to the precision the task requires.
  • Using a zero base with a negative exponent: 0 raised to a negative power would require division by zero and is undefined.

Very large powers may exceed the range that a calculator or computer can display, and very small values may be rounded to zero in limited-precision systems. A rounded decimal is an approximation, not always an exact representation; for instance, 1/3 has an indefinitely repeating decimal expansion.

Frequently Asked Questions

How do I calculate a number to the power of another number?
Enter the first number as the base and the second as the exponent. For a positive whole-number exponent, multiply the base by itself that many times; the calculator applies the same power rules to other supported real inputs.

What is a power function?
A power function has the form f(x) = xⁿ, where x is the input and n is a fixed exponent. More generally, xⁿ is the value of raising a base x to an exponent n.

What does a negative exponent mean?
A negative exponent means take the reciprocal of the corresponding positive power: x⁻ⁿ = 1/xⁿ. The base cannot be zero, because division by zero is undefined.

Can I raise a negative number to a fractional power?
Sometimes. A negative number raised to a fraction with an odd root, such as (−8)^(1/3), can have a real result. An even root such as (−8)^(1/2) has no real result, although it can be evaluated using complex numbers.

Why is my answer different when I use parentheses?
Because standard order of operations evaluates exponents before a leading negative sign. Thus −2⁴ means −16, while (−2)⁴ means 16. Parentheses specify whether the negative sign belongs to the base.

Related

Formula used
in base | Base (x) | - | 2 | - | -
in exp | Exponent (n) | - | 5 | - | -
out power | Power function value (x^n) | - | base ^ exp | 6

Each line is one input (in, sel, list) or one result (out: label, unit, formula, decimals). How the calculators work

Method: the standard formula for this calculation, rounded as each result states. See how the calculators work or report an error.

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