Casio fx-991EX vs Hp 50g speed difference
07-25-2018, 06:32 PM
Post: #13
 Albert Chan Senior Member Posts: 2,516 Joined: Jul 2018
RE: Casio fx-991EX vs Hp 50g speed difference
Just learned there is a trick to use Romberg's method for periodic function:
Casio keisan on-line Romberg Integration calculator, option non-linear substitution

Code:
def nonlinear(f, a, b):     c, d = (b-a)/4, (b+a)/2     return lambda u, k=3*c: k*(1 - u*u) * f(c*u*(3-u*u) + d)

Just integrate above transformed f, from -1 to 1:

$$\int_0^{200}sin(x) dx$$ = $$\int_{-1}^{1}150(1-u^2) sin[50u (3 - u^2) + 100] du$$

On my Casio FX-115MS, it had gotten the sin(x) integral wrong: -96.581

With transformed integral, after 3 minutes 45 seconds, I got 0.51281 :-)

Amazingly, Mathematica can solve the messy transformed integral symbolically: 2 (sin(100))^2
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 Messages In This Thread Casio fx-991EX vs Hp 50g speed difference - Tugdual - 07-13-2018, 08:50 PM RE: Casio fx-991EX vs Hp 50g speed difference - StephenG1CMZ - 07-13-2018, 10:36 PM RE: Casio fx-991EX vs Hp 50g speed difference - Carsen - 07-13-2018, 11:13 PM RE: Casio fx-991EX vs Hp 50g speed difference - Thomas Okken - 07-14-2018, 01:45 AM RE: Casio fx-991EX vs Hp 50g speed difference - Albert Chan - 07-14-2018, 03:17 AM RE: Casio fx-991EX vs Hp 50g speed difference - pier4r - 07-14-2018, 10:27 AM RE: Casio fx-991EX vs Hp 50g speed difference - ijabbott - 07-14-2018, 03:10 PM RE: Casio fx-991EX vs Hp 50g speed difference - Tugdual - 07-16-2018, 07:07 AM RE: Casio fx-991EX vs Hp 50g speed difference - brickviking - 07-18-2018, 04:28 AM RE: Casio fx-991EX vs Hp 50g speed difference - Albert Chan - 07-25-2018, 01:50 AM RE: Casio fx-991EX vs Hp 50g speed difference - Albert Chan - 07-25-2018, 12:55 PM RE: Casio fx-991EX vs Hp 50g speed difference - Carsen - 07-25-2018, 02:44 AM RE: Casio fx-991EX vs Hp 50g speed difference - Albert Chan - 07-25-2018 06:32 PM RE: Casio fx-991EX vs Hp 50g speed difference - Carsen - 07-25-2018, 08:07 PM RE: Casio fx-991EX vs Hp 50g speed difference - Albert Chan - 07-25-2018, 10:13 PM RE: Casio fx-991EX vs Hp 50g speed difference - Carsen - 07-26-2018, 03:01 AM RE: Casio fx-991EX vs Hp 50g speed difference - Carsen - 07-26-2018, 04:53 PM RE: Casio fx-991EX vs Hp 50g speed difference - Albert Chan - 07-26-2018, 03:28 AM RE: Casio fx-991EX vs Hp 50g speed difference - Albert Chan - 07-26-2018, 07:08 PM RE: Casio fx-991EX vs Hp 50g speed difference - gomefun2 - 09-03-2018, 07:40 PM

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