Elementary Functions - 4.13 Lambert -Function
DLMF | Formula | Constraints | Maple | Mathematica | Symbolic Maple |
Symbolic Mathematica |
Numeric Maple |
Numeric Mathematica |
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4.13.E1 | We^{W} = x |
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W*exp(W) = x
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W*Exp[W] == x
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Failure | Failure | Failed [30 / 30] Result: -.263026030+2.030302705*I
Test Values: {W = 1/2*3^(1/2)+1/2*I, x = 1.5}
Result: .736973970+2.030302705*I
Test Values: {W = 1/2*3^(1/2)+1/2*I, x = .5}
Result: -.763026030+2.030302705*I
Test Values: {W = 1/2*3^(1/2)+1/2*I, x = 2}
Result: -2.096603674+.1092863076*I
Test Values: {W = -1/2+1/2*I*3^(1/2), x = 1.5}
... skip entries to safe data |
Failed [30 / 30]
Result: Complex[-0.2630260306572938, 2.0303027048207967]
Test Values: {Rule[W, Power[E, Times[Complex[0, Rational[1, 6]], Pi]]], Rule[x, 1.5]}
Result: Complex[0.7369739693427062, 2.0303027048207967]
Test Values: {Rule[W, Power[E, Times[Complex[0, Rational[1, 6]], Pi]]], Rule[x, 0.5]}
... skip entries to safe data |
4.13#Ex1 | \LambertWp@{-1/e} = \LambertWm@{-1/e} |
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LambertW(0, - 1/exp(1)) = LambertW(-1, - 1/exp(1))
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ProductLog[0, - 1/E] == ProductLog[-1, - 1/E]
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Successful | Successful | - | Successful [Tested: 1] |
4.13#Ex1 | \LambertWm@{-1/e} = -1 |
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LambertW(-1, - 1/exp(1)) = - 1
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ProductLog[-1, - 1/E] == - 1
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Successful | Successful | - | Successful [Tested: 1] |
4.13#Ex2 | \LambertWp@{0} = 0 |
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LambertW(0, 0) = 0
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ProductLog[0, 0] == 0
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Successful | Successful | - | Successful [Tested: 1] |
4.13#Ex3 | \LambertWp@{e} = 1 |
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LambertW(0, exp(1)) = 1
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ProductLog[0, E] == 1
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Successful | Successful | - | Successful [Tested: 1] |
4.13#Ex4 | U+\ln@@{U} = x |
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U + ln(U) = x
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U + Log[U] == x
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Failure | Failure | Failed [30 / 30] Result: -.6339745958+1.023598776*I
Test Values: {U = 1/2*3^(1/2)+1/2*I, x = 1.5}
Result: .3660254042+1.023598776*I
Test Values: {U = 1/2*3^(1/2)+1/2*I, x = .5}
Result: -1.133974596+1.023598776*I
Test Values: {U = 1/2*3^(1/2)+1/2*I, x = 2}
Result: -2.000000000+2.960420506*I
Test Values: {U = -1/2+1/2*I*3^(1/2), x = 1.5}
... skip entries to safe data |
Failed [30 / 30]
Result: Complex[-0.6339745962155613, 1.0235987755982987]
Test Values: {Rule[U, Power[E, Times[Complex[0, Rational[1, 6]], Pi]]], Rule[x, 1.5]}
Result: Complex[0.3660254037844387, 1.0235987755982987]
Test Values: {Rule[U, Power[E, Times[Complex[0, Rational[1, 6]], Pi]]], Rule[x, 0.5]}
... skip entries to safe data |
4.13#Ex5 | U = U(x) |
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U = U*(x)
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U == U*(x)
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Failure | Failure | Failed [30 / 30] Result: -.4330127020-.2500000000*I
Test Values: {U = 1/2*3^(1/2)+1/2*I, x = 1.5}
Result: .4330127020+.2500000000*I
Test Values: {U = 1/2*3^(1/2)+1/2*I, x = .5}
Result: -.8660254040-.5000000000*I
Test Values: {U = 1/2*3^(1/2)+1/2*I, x = 2}
Result: .2500000000-.4330127020*I
Test Values: {U = -1/2+1/2*I*3^(1/2), x = 1.5}
... skip entries to safe data |
Failed [30 / 30]
Result: Complex[-0.4330127018922193, -0.24999999999999994]
Test Values: {Rule[U, Power[E, Times[Complex[0, Rational[1, 6]], Pi]]], Rule[x, 1.5]}
Result: Complex[0.43301270189221935, 0.24999999999999997]
Test Values: {Rule[U, Power[E, Times[Complex[0, Rational[1, 6]], Pi]]], Rule[x, 0.5]}
... skip entries to safe data |
4.13#Ex5 | U(x) = \LambertW@{e^{x}} |
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U(x) = LambertW(exp(x))
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U[x] == ProductLog[Exp[x]]
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Failure | Failure | Failed [30 / 30] Result: .34078386e-1+.7500000000*I
Test Values: {U = 1/2*3^(1/2)+1/2*I, x = 1.5}
Result: -.3332359062+.2500000000*I
Test Values: {U = 1/2*3^(1/2)+1/2*I, x = .5}
Result: .174905209+1.*I
Test Values: {U = 1/2*3^(1/2)+1/2*I, x = 2}
Result: -2.014959720+1.299038106*I
Test Values: {U = -1/2+1/2*I*3^(1/2), x = 1.5}
... skip entries to safe data |
Failed [30 / 30]
Result: Complex[0.0340783855511575, 0.7499999999999999]
Test Values: {Rule[U, Power[E, Times[Complex[0, Rational[1, 6]], Pi]]], Rule[x, 1.5]}
Result: Complex[-0.333235906269531, 0.24999999999999997]
Test Values: {Rule[U, Power[E, Times[Complex[0, Rational[1, 6]], Pi]]], Rule[x, 0.5]}
... skip entries to safe data |
4.13.E5 | \LambertWp@{x} = \sum_{n=1}^{\infty}(-1)^{n-1}\frac{n^{n-2}}{(n-1)!}x^{n} |
LambertW(0, x) = sum((- 1)^(n - 1)*((n)^(n - 2))/(factorial(n - 1))*(x)^(n), n = 1..infinity)
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ProductLog[0, x] == Sum[(- 1)^(n - 1)*Divide[(n)^(n - 2),(n - 1)!]*(x)^(n), {n, 1, Infinity}, GenerateConditions->None]
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Failure | Successful | Error | Successful [Tested: 0] | |
4.13.E6 | \LambertW@{-e^{-1-(t^{2}/2)}} = \sum_{n=0}^{\infty}(-1)^{n-1}c_{n}t^{n} |
LambertW(- exp(- 1 -((t)^(2)/2))) = sum((- 1)^(n - 1)* c[n]*(t)^(n), n = 0..infinity)
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ProductLog[- Exp[- 1 -((t)^(2)/2)]] == Sum[(- 1)^(n - 1)* Subscript[c, n]*(t)^(n), {n, 0, Infinity}, GenerateConditions->None]
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Failure | Failure | Failed [60 / 60] Result: Float(infinity)+Float(infinity)*I
Test Values: {t = -1.5, c[n] = 1/2*3^(1/2)+1/2*I}
Result: Float(infinity)+Float(infinity)*I
Test Values: {t = -1.5, c[n] = -1/2+1/2*I*3^(1/2)}
Result: Float(infinity)+Float(infinity)*I
Test Values: {t = -1.5, c[n] = 1/2-1/2*I*3^(1/2)}
Result: Float(infinity)+Float(infinity)*I
Test Values: {t = -1.5, c[n] = -1/2*3^(1/2)-1/2*I}
... skip entries to safe data |
Failed [60 / 60]
Result: Plus[-0.13696418431579768, Times[-1.0, NSum[Times[Power[-1.5, n], Power[-1, Plus[-1, n]], Power[E, Times[Complex[0, Rational[1, 6]], Pi]]]
Test Values: {n, 0, DirectedInfinity[1]}, Rule[GenerateConditions, None]]]], {Rule[t, -1.5], Rule[Subscript[c, n], Power[E, Times[Complex[0, Rational[1, 6]], Pi]]]}
Result: Plus[-0.13696418431579768, Times[-1.0, NSum[Times[Power[-1.5, n], Power[-1, Plus[-1, n]], Power[E, Times[Complex[0, Rational[2, 3]], Pi]]]
Test Values: {n, 0, DirectedInfinity[1]}, Rule[GenerateConditions, None]]]], {Rule[t, -1.5], Rule[Subscript[c, n], Power[E, Times[Complex[0, Rational[2, 3]], Pi]]]}
... skip entries to safe data | |
4.13.E7 | c_{0} = 1,c_{1} |
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c[0] = 1; c[1] |
Subscript[c, 0] == 1
Subscript[c, 1] |
Skipped - no semantic math | Skipped - no semantic math | - | - |
4.13.E8 | c_{n} = \frac{1}{n+1}\left(c_{n-1}-\sum_{k=2}^{n-1}kc_{k}c_{n+1-k}\right) |
c[n] = (1)/(n + 1)*(c[n - 1]- sum(k*c[k]*c[n + 1 - k], k = 2..n - 1)) |
Subscript[c, n] == Divide[1,n + 1]*(Subscript[c, n - 1]- Sum[k*Subscript[c, k]*Subscript[c, n + 1 - k], {k, 2, n - 1}, GenerateConditions->None]) |
Skipped - no semantic math | Skipped - no semantic math | - | - | |
4.13.E9 | 1\cdot 3\cdot 5\cdots(2n+1)c_{2n+1} = g_{n} |
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1 * 3 * 5*(2*n + 1)*c[2*n + 1] = g[n] |
1 * 3 * 5*(2*n + 1)*Subscript[c, 2*n + 1] == Subscript[g, n] |
Skipped - no semantic math | Skipped - no semantic math | - | - |