Skip to content

Commit ca50618

Browse files
Read a derivative of a product with a sine, a cosine or an exponential raised from nothing in it (#1980)
Fifteen of Rubi's 4.7.6, 4.7.7, 6.1.4, 6.2.4 and 6.7.1 are exact derivatives, or one beside an integral that is answered, written out: - The derivative of a product of powers may raise a sine, a cosine or an exponential from nothing, one at a time, and a power with x in its base and exponent is read with its exponent's derivative times its base's logarithm: cosh(x)^x (ln(cosh(x)) + x tanh(x)) is (cosh(x)^x)'. - Where the brackets are not proportional, the integrand may be a constant times that derivative and a constant times the functions alone. - A denominator with a negative exponential in it is multiplied above and below by the positive one. - cos(u)^2 + sin(u)^2 in a sum is written as 1. - A polynomial factor that is a constant multiple of a substitution's du/dx is divided out. Rubi pocket (1,901 rows): 1829 -> 1844 solved. The moves re-run alone gain 15 rows (4.7.6:53-55, 4.7.7:90, 977, 1180, 1199, 1201, 6.1.4:14, 19, 6.2.4:14, 19, 6.7.1:634, 766, 1252), none lost; 3.2.1:292 allocates the same on both builds at a 60 s budget. Part of #233. Claude-Session: https://claude.ai/code/session_012sonx8iAspMiwRwokT1Ura Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
1 parent 31dc45e commit ca50618

4 files changed

Lines changed: 616 additions & 30 deletions

File tree

‎BREAKING-CHANGES.md‎

Lines changed: 32 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2584,6 +2584,38 @@ is written so, after the substitutions, and the factor goes in front of the answ
25842584
| `"(1/(1 - x^2))^(3/2)".ToEntity().Integrate("x")` | `integral(...)` | `sgn(1 - x^2) x/sqrt(1 - x^2)` |
25852585
| `"(c/(a + b*x^2))^(3/2)".ToEntity().Integrate("x")` | `integral(...)` | `(c/(a + b x^2))^(3/2) (a + b x^2)^(3/2) x/(a sqrt(a + b x^2))` |
25862586

2587+
### A derivative of a product is read with a sine, a cosine or an exponential raised from nothing in it
2588+
2589+
**Answers where there were none.** Thirteen of Rubi's 4.7.6, 4.7.7, 6.1.4, 6.2.4 and 6.7.1 were declined, each an
2590+
exact derivative, or one beside an integral that is answered, written out
2591+
([#233](https://github.com/asc-community/AngouriMath/issues/233)):
2592+
- The derivative of a product of powers may raise a sine, a cosine or an exponential from nothing, one at a time:
2593+
`F^(c (a + b x)) (f x)^m (e x cos(d + e x) + (m + b c x ln F) sin(d + e x))/x` is
2594+
`(F^(c (a + b x)) (f x)^m sin(d + e x))'`. A power with x in its base and in its exponent is read with its exponent's
2595+
derivative times its base's logarithm, so `cosh(x)^x (ln(cosh(x)) + x tanh(x))` is `(cosh(x)^x)'`.
2596+
- Where the brackets are not proportional, the integrand may be a constant times that derivative and a constant times
2597+
the functions alone: `sinh(Q)/x^2 - b cosh(Q)/x` is `(-sinh(Q)/x)' + 2 c cosh(Q)` for `Q = a + b x + c x^2`, and the
2598+
second term is answered in error functions.
2599+
- A denominator with a negative exponential in it is multiplied above and below by the positive one:
2600+
`(cos(x) + sin(x))/(e^(-x) + sin(x))` is the logarithmic derivative of `1 + e^x sin(x)`.
2601+
- `cos(u)^2 + sin(u)^2` in a sum is written as `1`, so `e^(cos(x)^2 + sin(x)^2)` is `e`.
2602+
- A polynomial factor that is a constant multiple of a substitution's `du/dx` is divided out:
2603+
`(x + b/(2 c)) tan(a + b x + c x^2)` is `-ln(cos(a + b x + c x^2))/(2 c)`.
2604+
2605+
Two more of 4.7.6, `F^(c (a + b x)) (e x cos(d + e x) + (b c x ln F - 1) sin(d + e x))/x^2` and its `x^3` twin, were
2606+
declined by 2.5.0 and answered by the unreleased master in exponential integrals, 1,209 and 2,331 characters; they are
2607+
the product `F^(c (a + b x)) sin(d + e x)/x` and its twin now, 50 and 53.
2608+
2609+
| Input | Was (2.5.0) | Now |
2610+
|---|---|---|
2611+
| `"g^(c*(a+b*x))*(f*x)^m*(k*x*cos(d+k*x)+(m+b*c*x*ln(g))*sin(d+k*x))/x".ToEntity().Integrate("x")` | `integral(...)` | 78 characters |
2612+
| `"-b*cosh(a+b*x+c*x^2)/x+sinh(a+b*x+c*x^2)/x^2".ToEntity().Integrate("x")` | `integral(...)` | 294 characters |
2613+
| `"cosh(x)^x*(ln(cosh(x))+x*tanh(x))".ToEntity().Integrate("x")` | `integral(...)` | `((e^x + e^(-x))/2)^x` |
2614+
| `"(cos(x)+sin(x))/(1/e^x+sin(x))".ToEntity().Integrate("x")` | `integral(...)` | `ln(1 + sin(x) e^x)` |
2615+
| `"e^(cos(x)^2+sin(x)^2)".ToEntity().Integrate("x")` | `integral(...)` | `e x` |
2616+
| `"1/2*b*tan(a+b*x+c*x^2)/c+x*tan(a+b*x+c*x^2)".ToEntity().Integrate("x")` | `integral(...)` | 45 characters |
2617+
| `"g^(c*(a+b*x))*(k*x*cos(d+k*x)+(-1+b*c*x*ln(g))*sin(d+k*x))/x^2".ToEntity().Integrate("x")` | `integral(...)` | 50 characters, where the unreleased master gave 1,209 |
2618+
25872619
### A sum that is the derivative of a product of powers is read as one
25882620

25892621
**Answers where there were none.** `m x^(m - 1) (a + b x^n)^p + b n p x^(m + n - 1) (a + b x^n)^(p - 1)` is

0 commit comments

Comments
 (0)