An Amplitude

The <b style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: "Helvetica Neue", Helvetica, "Nimbus Sans L", Arial, "Liberation Sans", sans-serif; vertical-align: baseline; background-image: none; background-position: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; color: rgb(34, 34, 34);">amplitude of a <a href="https://en.wikipedia.org/wiki/Periodic_function" title="Periodic function" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: "Helvetica Neue", Helvetica, "Nimbus Sans L", Arial, "Liberation Sans", sans-serif; vertical-align: baseline; background-image: none; background-position: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); color: rgb(90, 54, 150);">periodic</a> <a href="https://en.wikipedia.org/wiki/Variable(mathematics)" title="Variable (mathematics)" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: "Helvetica Neue", Helvetica, "Nimbus Sans L", Arial, "Liberation Sans", sans-serif; vertical-align: baseline; background-image: none; background-position: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); color: rgb(90, 54, 150);">variable</a> is a measure of its change over a single <a href="https://en.wikipedia.org/wiki/Period(mathematics)" title="Period (mathematics)" class="mw-redirect" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: "Helvetica Neue", Helvetica, "Nimbus Sans L", Arial, "Liberation Sans", sans-serif; vertical-align: baseline; background-image: none; background-position: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); color: rgb(90, 54, 150);">period</a>(such as <a href="https://en.wikipedia.org/wiki/Period(physics)" title="Period (physics)" class="mw-redirect" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: "Helvetica Neue", Helvetica, "Nimbus Sans L", Arial, "Liberation Sans", sans-serif; vertical-align: baseline; background-image: none; background-position: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); color: rgb(90, 54, 150);">time</a> or <a href="https://en.wikipedia.org/wiki/Wavelength" title="Wavelength" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: "Helvetica Neue", Helvetica, "Nimbus Sans L", Arial, "Liberation Sans", sans-serif; vertical-align: baseline; background-image: none; background-position: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); color: rgb(90, 54, 150);">spatial period</a>). There are various definitions of amplitude (see below), which are all <a href="https://en.wikipedia.org/wiki/Function(mathematics)" title="Function (mathematics)" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: "Helvetica Neue", Helvetica, "Nimbus Sans L", Arial, "Liberation Sans", sans-serif; vertical-align: baseline; background-image: none; background-position: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); color: rgb(90, 54, 150);">functions</a> of the magnitude of the difference between the variable's <a href="https://en.wikipedia.org/wiki/Maxima_and_minima" title="Maxima and minima" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: "Helvetica Neue", Helvetica, "Nimbus Sans L", Arial, "Liberation Sans", sans-serif; vertical-align: baseline; background-image: none; background-position: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); color: rgb(90, 54, 150);">extreme values</a>. In older texts the <a href="https://en.wikipedia.org/wiki/Phase_(waves)" title="Phase (waves)" style="margin: 0px; padding: 0px; border: 0px; font-variant-numeric: inherit; font-variant-east-asian: inherit; font-stretch: inherit; line-height: inherit; font-family: "Helvetica Neue", Helvetica, "Nimbus Sans L", Arial, "Liberation Sans", sans-serif; vertical-align: baseline; background-image: none; background-position: initial; background-repeat: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); color: rgb(90, 54, 150);">phase</a> is sometimes called the amplitude.