HP 42S 8 Numeric Integration

8 Numeric Integration

Suppose we want to solve numerically a integral of the form

∫ba f  xdx

we write the function in the same way we did in the solver case.

Example: Calculate ∫10 x2 dx .

First we enter the function as a program

01 LBL “FX”

02 MVAR “X” (also available in ∫f(x) menu)

03 RCL X

04X↑2

05RTN

06END

Then we go to the ∫f(x) menu and what we have is “Select ∫f(x) Program”. In our case we select FX then what appears is “Set Vars; Select ∫var” and we select X (before that we may set some variables/constants if needed) and then we have to set LLIM (lower limit), ULIM (upper limit) and ACC (Accuracy factor). In our case 0 LLIM and 1 ULIM and for ACC we can use 0.001. Now just press ∫ and we find 0.33333028. If we set ACC to 0.000001 we will have 0.33333333333. In the Free42 program the results may be little different.