UnitTriangle[x]
represents the unit triangle function on the interval
.
UnitTriangle[x1,x2,…]
represents the multidimensional unit triangle function on the interval
.
UnitTriangle
UnitTriangle[x]
represents the unit triangle function on the interval
.
UnitTriangle[x1,x2,…]
represents the multidimensional unit triangle function on the interval
.
Details
- UnitTriangle[x] is equivalent to Piecewise[{{x+1,-1≤x<0},{1-x,0≤x≤1}}].
- UnitTriangle can be used in integrals and integral transforms.
- UnitTriangle has attribute Orderless.
- UnitTriangle automatically threads over lists. »
Examples
open all close allBasic Examples (4)
UnitTriangle[0.8]Plot[UnitTriangle[x], {x, -2, 2}]Plot3D[UnitTriangle[x, y], {x, -1, 1}, {y, -1, 1}]UnitTriangle is a piecewise function:
PiecewiseExpand[UnitTriangle[x]]Scope (36)
Numerical Evaluation (7)
UnitTriangle[-1]UnitTriangle[1 / 4]UnitTriangle[1, Pi, 5.3]N[UnitTriangle[-1 / 7], 50]For inputs between -1 and 1, the precision of the output tracks the precision of the input:
UnitTriangle[.555555555555555555555555]UnitTriangle[.5]For inputs outside that range, the result is exact:
UnitTriangle[1.2]Evaluate efficiently at high precision:
UnitTriangle[-1 / 3`100]//TimingUnitTriangle[5 / 11`10000000];//TimingUnitTriangle threads over lists:
UnitTriangle[{-3, -1, 0, 1 / 3, 1}]Compute the elementwise values of an array using automatic threading:
UnitTriangle[{{1 / 2, -1}, {0, 1 / 2}}, 1 / 2]Or compute the matrix UnitTriangle function using MatrixFunction:
MatrixFunction[UnitTriangle[#, 1 / 2]&, {{1 / 2, -1}, {0, 1 / 2}}]//FullSimplifyCompute average-case statistical intervals using Around:
UnitTriangle[ Around[1 / 2, 0.01], 1 / 2]Specific Values (4)
Values of UnitTriangle at fixed points:
Table[UnitTriangle[n ], {n, -1, 1, 1 / 3}]UnitTriangle[0]PiecewiseExpand[UnitTriangle[x], 0 < x < 2]PiecewiseExpand[UnitTriangle[a, a, a, a], 0 < a < 1]Simplify[UnitTriangle[b, a], a < -1 && b > 0]Find a value of x for which UnitTriangle[x]=0.4:
xval = x /. FindRoot[UnitTriangle[x] == 0.4, {x, 0.5}]Plot[UnitTriangle[x], {x, -2, 2}, Epilog -> Style[Point[{xval, UnitTriangle[xval]}], PointSize[Large], Red], ExclusionsStyle -> Dotted]Visualization (4)
Plot the UnitTriangle function:
Plot[UnitTriangle[x], {x, -2, 2}]Visualize scaled UnitTriangle functions:
Plot[{UnitTriangle[x], UnitTriangle[x / 2], UnitTriangle[2x]}, {x, -3, 3}, PlotLegends -> "Expressions"]Visualize the composition of UnitTriangle with a periodic function:
Plot[UnitTriangle[Sin[x]], {x, -2Pi, 2Pi}]Plot UnitTriangle in three dimensions:
Plot3D[UnitTriangle[x, y], {x, -1.5, 1.5}, {y, -1.5, 1.5}, ColorFunction -> "SouthwestColors", Exclusions -> None, PlotRange -> All]Function Properties (11)
Function domain of UnitTriangle:
FunctionDomain[UnitTriangle[x], x]It is restricted to real inputs:
FunctionDomain[UnitTriangle[x], x, Complexes]Function range of UnitTriangle:
FunctionRange[UnitTriangle[x], x, y]UnitTriangle is an even function:
UnitTriangle[-x]The area of the UnitTriangle is 1:
Integrate[UnitTriangle[x], {x, -∞, ∞}]UnitTriangle is not an analytic function:
FunctionAnalytic[UnitTriangle[x], x]FunctionSingularities[UnitTriangle[x], x]However, it is continuous everywhere:
FunctionDiscontinuities[UnitTriangle[x], x]Verify the claim at one of its singular points:
Underscript[, x -> 0]UnitTriangle[x] == UnitTriangle[0]UnitTriangle is neither nondecreasing nor nonincreasing:
FunctionMonotonicity[UnitTriangle[x], x]UnitTriangle is not injective:
FunctionInjective[UnitTriangle[x], x]Plot[{UnitTriangle[x], .5}, {x, -7, 7}]UnitTriangle is not surjective:
FunctionSurjective[UnitTriangle[x], x]Plot[{UnitTriangle[x] + 1, -1}, {x, -5, 5}]UnitTriangle is non-negative:
FunctionSign[UnitTriangle[x], x]UnitTriangle is neither convex nor concave:
FunctionConvexity[UnitTriangle[x], x]TraditionalForm typesetting:
UnitTriangle[x]//TraditionalFormDifferentiation and Integration (6)
First derivative with respect to x:
D[UnitTriangle[x], x]Higher-order derivatives with respect to x:
Table[D[UnitTriangle[x], {x, k}], {k, 2, 3}]//FullSimplifyFirst derivative with respect to z:
D[UnitTriangle[x, y, z], z]Series expansion at the origin:
Series[UnitTriangle[ x], {x, 0, 3}]//NormalCompute the indefinite integral using Integrate:
Integrate[UnitTriangle[x], x]Verify the anti-derivative away from the singular points:
FullSimplify[D[%, x] == UnitTriangle[x], x ≠ 0 && x ≠ 1 && x ≠ -1 && x∈Reals]Integrate[UnitTriangle[x], {x, 0, 5}]Integral Transforms (4)
FourierTransform of UnitTriangle is a squared Sinc function:
FourierTransform[UnitTriangle[x], x, t, FourierParameters -> {1, 1}]Plot[%, {t, -15, 15}]FourierSeries[UnitTriangle[x], x, 5]// FullSimplifyPlot[{%, UnitTriangle[x]}, {x, -2, 2}, Exclusions -> None]Find the LaplaceTransform of UnitTriangle:
LaplaceTransform[UnitTriangle[x], x, t]Plot[%, {t, -3, 3}, PlotRange -> All]The convolution of UnitTriangle with itself:
Convolve[UnitTriangle[x], UnitTriangle[x], x, y]Plot[{%, UnitTriangle[y]}, {y, -2, 2}]Applications (4)
Integrate a piecewise function involving UnitTriangle symbolically and numerically:
Plot[Tanh[x] UnitTriangle[3x - 1], {x, 0, 1}]Integrate[Tanh[x] UnitTriangle[3x - 1], {x, -1, 1}]N[%]NIntegrate[Tanh[x]UnitTriangle[3x - 1], {x, -1, 1}]Solve a differential equation involving UnitBox and UnitTriangle:
DSolve[y'[x] + UnitBox[x - 1 / 2] y[x] == UnitTriangle[x] && y[0] == 3, y, x]Plot[y[x] /. %, {x, -2, 2}]Visualize discontinuities in the wavelet domain:
data = Table[UnitTriangle[x], {x, -2, 2, 4 / 1023}];ListLinePlot[data]Detail coefficients in the region of discontinuities have larger values:
dwd = DiscreteWaveletTransform[data, DaubechiesWavelet[3], 5, Padding -> "Reflected"];WaveletScalogram[dwd, {___, 1}, Method -> "Inverse" -> True, ColorFunction -> "BlueGreenYellow"]Generate data from some distribution:
list = Join[
({Cos[#], Sin[#]} + RandomReal[{-0.1, 0.1}, 2])& /@ RandomVariate[NormalDistribution[Pi, 1], 1000],
RandomVariate[BinormalDistribution[{1, -1}, {.3, .5}, 0], 1000],
RandomVariate[BinormalDistribution[{1, 1}, {.3, .5}, 0], 1000]
];ListPlot[list]Apply mean shift until all data points have converged:
res = MeanShift[list, .4, MaxIterations -> ∞, DistanceFunction -> SquaredEuclideanDistance, Weights -> UnitTriangle, Tolerance -> 10 ^ -10];Gather the result into clusters:
c = ArrayComponents[res, 1];
clust = GatherBy[Transpose[{list, c}], Last];
clust = #[[All, 1]]& /@ clust;ListPlot[clust]Properties & Relations (4)
The derivative of UnitTriangle is a piecewise function:
D[UnitTriangle[x], x]The derivative of HeavisideLambda is a distribution:
D[HeavisideLambda[x], x]At higher orders, the DiracDelta distribution appears:
D[HeavisideLambda[x], {x, 2}]Convert into Piecewise:
PiecewiseExpand[UnitTriangle[x]]PiecewiseExpand[Exp[x UnitTriangle[x]UnitTriangle[1 - UnitTriangle[x]]]]Multidimensional unit triangle function equals the product of 1D functions for each argument:
UnitTriangle[x, y, z] == UnitTriangle[x]UnitTriangle[y]UnitTriangle[z]Simplify[%]UnitTriangle is a special case of BSplineBasis:
{Plot[BSplineBasis[1, 1 / 2(x + 1)], {x, -2, 2}], Plot[UnitTriangle[x], {x, -2, 2}]}Related Guides
Related Links
History
Text
Wolfram Research (2008), UnitTriangle, Wolfram Language function, https://reference.wolfram.com/language/ref/UnitTriangle.html.
CMS
Wolfram Language. 2008. "UnitTriangle." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/UnitTriangle.html.
APA
Wolfram Language. (2008). UnitTriangle. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/UnitTriangle.html
BibTeX
@misc{reference.wolfram_2026_unittriangle, author="Wolfram Research", title="{UnitTriangle}", year="2008", howpublished="\url{https://reference.wolfram.com/language/ref/UnitTriangle.html}", note=[Accessed: 13-June-2026]}
BibLaTeX
@online{reference.wolfram_2026_unittriangle, organization={Wolfram Research}, title={UnitTriangle}, year={2008}, url={https://reference.wolfram.com/language/ref/UnitTriangle.html}, note=[Accessed: 13-June-2026]}