Activate

Activate[expr]

replaces all instances of Inactive[f] in expr with f.

Activate[expr,patt]

replaces only instances of Inactive[f] for which f matches the pattern patt.

Details and Options

  • With the option setting Heads->False, Activate does not enter heads of expressions and activate their parts.

Examples

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Basic Examples  (2)

Activate an Inactive expression:

Activate different parts of an inactive expression:

Scope  (7)

Define an inactive expression:

Evaluate the expression using Activate:

Create an inactive expression using Inactivate:

Evaluate the expression:

Inactivate the symbol g only:

Activate g:

Inactivate g and h:

Activate h:

Activate an inactive expression:

Activate all symbols except Integrate:

Prevent numeric functions from being activated:

Formally differentiating a Laplace transform:

Similarly differentiating wrt t and a:

Inactive special function expression:

Expression after automatic simplification:

Options  (1)

Heads  (1)

An inactive Derivative expression:

Activate the expression:

Use the option setting Heads->False to avoid activating Derivative:

Applications  (5)

Define a trigonometric expression with two inactive terms:

Activate different parts of the expression:

Define , leaving both the derivative and integral inactive:

Differentiate the integral without evaluating the integral:

Activate the integral to compute the final result:

Integrate without performing the differentiation:

Activate the differentiation to compute the final result:

The results are mathematically the same:

Solution for the three-dimensional Laplace equation in inactive integral form:

Obtain a particular solution by specifying the function f:

Visualize the solution:

Verify the solution:

Formula for summation by parts:

Verify the formula in a special case:

Evaluate the sum:

Explore vector identities:

Activating Curl is not very interesting:

Activating Div demonstrates the relation TemplateBox[{{(, TemplateBox[{v,  }, Curl], )},  }, Div]=0:

Properties & Relations  (4)

Inactive expressions can be evaluated using Activate:

Activate is the inverse of Inactivate:

Activate replaces all instances of inactive symbols in an expression:

Activate evaluates inactive expressions and allows parts of expressions to be inactive:

ReleaseHold evaluates expressions held in unevaluated form, and all parts are evaluated:

Neat Examples  (1)

Create a gallery of infinite products:

Introduced in 2014
 (10.0)