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29 changes: 29 additions & 0 deletions BREAKING-CHANGES.md
Original file line number Diff line number Diff line change
Expand Up @@ -747,6 +747,35 @@ they are written ([#718](https://github.com/asc-community/AngouriMath/issues/718
| `"1/((a + b*x^2)^(9/2)*(1 + x^2))".ToEntity().Integrate("x")` | `integral(...)` | the same, in 1 s |
| `"x^2/((a + b*x^2)^(7/2)*(c + d*x^2))".ToEntity().Integrate("x")` | `integral(...)` | the same by the sign of `c (a d - b c)`, in 1 s |

### A binomial differential with symbols in it, or a power of `x` that is not whole, is integrated

**Answers where there were none.** Chebyshev's theorem says when `x^m (a + b x^n)^(p/q)` has an
elementary antiderivative, and it is about the exponents only. The rule for it read whole `m` and
`n` and rational numbers for `a` and `b`, and declined the rest. It reads rational `m` and `n` and
anything free of `x` for `a` and `b` now, and a power of a multiple of `x`, `(c x)^(5/2)`, as
`x^(5/2)` times `(c x)^(5/2)/x^(5/2)`, which is constant on either side of zero. Where `m + 1 +
n (p/q + 1)` is zero the answer is the one product of powers it is. With a symbol in the
coefficients the rule is asked after the rules for a root of a quadratic and for a rational
function of `x^n` beside the root of its binomial, which answer what they share with it more
shortly. Rubi's 1.1.2.2 and 1.1.3.2, `(c x)^m (a + b x^n)^p`
([#718](https://github.com/asc-community/AngouriMath/issues/718)).

| Input | Was (2.5.0) | Now |
|---|---|---|
| `"x^2/(a + b*x^4)^(3/4)".ToEntity().Integrate("x")` | `integral(...)` | logarithms and an arctangent of `(a + b x^4)^(1/4)/x` |
| `"x^6*(a + b*x^4)^(1/4)".ToEntity().Integrate("x")` | `integral(...)` | the same, beside a rational function of it |
| `"x^(7/3)*(a + b*x^2)^(1/3)".ToEntity().Integrate("x")` | `integral(...)` | a rational function, two logarithms and an arctangent of `(a + b x^2)^(1/3)/x^(2/3)`, written in `x^(1/3)` |
| `"(c*x)^(5/2)/(a - b*x^2)^(3/4)".ToEntity().Integrate("x")` | `integral(...)` | `(c x)^(5/2)/x^(5/2)` times the same in `(a - b x^2)^(1/4)/x^(1/2)` |
| `"(a - b*x^2)^(1/4)/(c*x)^(15/2)".ToEntity().Integrate("x")` | `integral(...)` | powers of `(a - b x^2)^(1/4)/(c x)^(1/2)` |

Of Rubi's 3,163 problems in those two files with an answer in functions the library has, 96 more
are answered than on the unreleased master, and none fewer. Nine that the unreleased master answered
are written otherwise: a rule ahead of this one takes the integrand apart and asks a sub-integral
that this one answers now, so the rule ahead finishes where it used to decline. Four of the nine come
out shorter and five longer -- `1/((c x)^(5/3) (a + b x^2)^(2/3))` was
`-3/(2 a) x (c x)^(-5/3) (a + b x^2)^(1/3)` there, and is the same function written in `x^(1/3)`.
2.5.0 declined all nine.

### A power of a multiple of a quadratic's derivative beside a power of the quadratic is a binomial

**Improvement, not silent.** `(b d + 2 c d x)^m (a + b x + c x^2)^p`, with a power that is not whole,
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