Plus42 algebraic expressions update

[Werner]

You can SOLVE an integral or INTEG a solved function; you can't nest INTEGs to calculate a double integral.
eg.
find a zero of the Bessel function

J0(x) = 1/PI * INT(0,PI,COS(x*SIN(t),t)

1.define the integrand

Code:

 LBL "J0i"
 RCL "T"
 SIN
 RCL* "X"
 COS
 END

2.define the function

Code:

 LBL "J0"
 MVAR "X"
 FC? 45
 STO "X"
 PGMINT "J0i"
 CLX
 STO "LLIM"
 PI
 STO "ULIM"
 5e-5
 STO "ACC"
 INTEG "T"
 PI
 /
 END

3.Invoke the interactive SOLVER, choose J0 etc.

Cheers, Werner