Get the square root of an expression—Wolfram Documentation (2024)

Sqrt[z]

or Get the square root of an expression—Wolfram Documentation (1) gives the square root of z.

Get the square root of an expression—Wolfram Documentation (2)

  • Mathematical function, suitable for both symbolic and numerical manipulation.
  • Get the square root of an expression—Wolfram Documentation (3) can be entered using Get the square root of an expression—Wolfram Documentation (4) or (@z).
  • Sqrt[z] is converted to Get the square root of an expression—Wolfram Documentation (5).
  • Sqrt[z^2] is not automatically converted to z.
  • Sqrt[a b] is not automatically converted to Sqrt[a]Sqrt[b].
  • These conversions can be done using PowerExpand, but will typically be correct only for positive real arguments.
  • For certain special arguments, Sqrt automatically evaluates to exact values.
  • Sqrt can be evaluated to arbitrary numerical precision.
  • Sqrt automatically threads over lists.
  • In StandardForm, Sqrt[z] is printed as Get the square root of an expression—Wolfram Documentation (6).
  • z can also be used for input. The character is entered as Get the square root of an expression—Wolfram Documentation (7)sqrtGet the square root of an expression—Wolfram Documentation (8) or \[Sqrt].
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Basic Examples(6)

Evaluate numerically:

Enter Get the square root of an expression—Wolfram Documentation (9) using Get the square root of an expression—Wolfram Documentation (10):

Negative numbers have imaginary square roots:

Plot over a subset of the reals:

Plot over a subset of the complexes:

Get the square root of an expression—Wolfram Documentation (11) is not necessarily equal to Get the square root of an expression—Wolfram Documentation (12):

It can be simplified to Get the square root of an expression—Wolfram Documentation (13) if one assumes Get the square root of an expression—Wolfram Documentation (14):

Scope(38)

Numerical Evaluation(6)

Evaluate numerically:

Evaluate to high precision:

The precision of the output tracks the precision of the input:

Complex number inputs:

Evaluate efficiently at high precision:

Sqrt can deal with realvalued intervals:

Sqrt threads elementwise over lists and matrices:

Specific Values(4)

Values of Sqrt at fixed points:

Values at zero:

Values at infinity:

Find a value of Get the square root of an expression—Wolfram Documentation (15) for which Get the square root of an expression—Wolfram Documentation (16) using Solve:

Substitute in the result:

Visualize the result:

Visualization(4)

Plot the real and imaginary parts of the Sqrt function:

Compare the real and imaginary parts of Get the square root of an expression—Wolfram Documentation (17) and Get the square root of an expression—Wolfram Documentation (18) (Surd[x,2]):

Plot the real part of Get the square root of an expression—Wolfram Documentation (19):

Plot the imaginary part of Get the square root of an expression—Wolfram Documentation (20):

Polar plot with Get the square root of an expression—Wolfram Documentation (21):

Function Properties(10)

The real domain of Sqrt:

It is defined for all complex values:

Sqrt achieves all non-negative values on the reals:

The range for complex values is the right half-plane, excluding the negative imaginary axis:

Find limits at branch cuts:

Enter a character as Get the square root of an expression—Wolfram Documentation (22)sqrtGet the square root of an expression—Wolfram Documentation (23) or \[Sqrt], followed by a number:

Get the square root of an expression—Wolfram Documentation (24) is not an analytic function:

Nor is it meromorphic:

Get the square root of an expression—Wolfram Documentation (25) is neither non-decreasing nor non-increasing:

However, it is increasing where it is real valued:

Get the square root of an expression—Wolfram Documentation (26) is injective:

Not surjective:

Get the square root of an expression—Wolfram Documentation (27) is non-negative on its domain of definition:

Get the square root of an expression—Wolfram Documentation (28) has a branch cut singularity for Get the square root of an expression—Wolfram Documentation (29):

However, it is continuous at the origin:

Get the square root of an expression—Wolfram Documentation (30) is neither convex nor concave:

However, it is concave where it is real valued:

Differentiation(3)

The first derivative with respect to z:

Higher derivatives with respect to z:

Plot the higher derivatives with respect to z:

Formula for the Get the square root of an expression—Wolfram Documentation (31)Get the square root of an expression—Wolfram Documentation (32) derivative with respect to z:

Integration(3)

Compute the indefinite integral using Integrate:

Verify the anti-derivative:

Definite integral:

More integrals:

Series Expansions(4)

Find the Taylor expansion using Series:

Plots of the first three approximations around Get the square root of an expression—Wolfram Documentation (33):

The general term in the series expansion using SeriesCoefficient:

The first-order Fourier series:

The Taylor expansion at a generic point:

Function Identities and Simplifications(4)

Primary definition:

Connection with Exp and Log:

Get the square root of an expression—Wolfram Documentation (34) is not automatically replaced by Get the square root of an expression—Wolfram Documentation (35):

It can be simplified to Get the square root of an expression—Wolfram Documentation (36) if one assumes Get the square root of an expression—Wolfram Documentation (37):

It can be simplified to Get the square root of an expression—Wolfram Documentation (38) if one assumes Get the square root of an expression—Wolfram Documentation (39):

PowerExpand can be used to force cancellation without assumptions:

Expand assuming real variables x and y:

Applications(4)

Roots of a quadratic polynomial:

Generate periodic continued fractions:

Solve a differential equation with Sqrt:

Compute an elliptic integral from the Sqrt function:

Properties & Relations(12)

Sqrt[x] and Surd[x,2] are the same for non-negative real values:

For negative reals, Sqrt gives an imaginary result, whereas the real-valued Surd reports an error:

Get the square root of an expression—Wolfram Documentation (40)

Reduce combinations of square roots:

Evaluate power series involving square roots:

Expand a complex square root assuming variables are real valued:

Factor polynomials with square roots in coefficients:

Simplify handles expressions involving square roots:

There are many subtle issues in handling square roots for arbitrary complex arguments:

PowerExpand expands forms involving square roots:

It generically assumes that all variables are positive:

Finite sums of integers and square roots of integers are algebraic numbers:

Take limits accounting for branch cuts:

Sqrt can be represented as a DifferentialRoot:

The generating function for Sqrt:

Possible Issues(3)

Square root is discontinuous across its branch cut along the negative real axis:

Sqrt[x^2] cannot automatically be reduced to x:

With x assumed positive, the simplification can be done:

Use PowerExpand to do the formal reduction:

Along the branch cut, these are not the same:

Neat Examples(2)

Approximation to GoldenRatio:

Riemann surface for square root:

Power CubeRoot Surd PowerExpand SqrtBox

Characters: \[Sqrt]

  • Some Mathematical Functions
  • Operators
  • Typing Square Roots
  • Arithmetic Functions
  • Elementary Functions
  • Mathematical Functions

Introduced in 1988 (1.0) | Updated in 1996 (3.0)

Wolfram Research (1988), Sqrt, Wolfram Language function, https://reference.wolfram.com/language/ref/Sqrt.html (updated 1996).

Text

Wolfram Research (1988), Sqrt, Wolfram Language function, https://reference.wolfram.com/language/ref/Sqrt.html (updated 1996).

CMS

Wolfram Language. 1988. "Sqrt." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 1996. https://reference.wolfram.com/language/ref/Sqrt.html.

APA

Wolfram Language. (1988). Sqrt. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Sqrt.html

BibTeX

@misc{reference.wolfram_2024_sqrt, author="Wolfram Research", title="{Sqrt}", year="1996", howpublished="\url{https://reference.wolfram.com/language/ref/Sqrt.html}", note=[Accessed: 21-June-2024]}

BibLaTeX

@online{reference.wolfram_2024_sqrt, organization={Wolfram Research}, title={Sqrt}, year={1996}, url={https://reference.wolfram.com/language/ref/Sqrt.html}, note=[Accessed: 21-June-2024]}

Get the square root of an expression—Wolfram Documentation (2024)

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