# Function Rkferr; Function Rsberr - HP 49g+ User Manual

Graphing calculator.

## Function RKFERR

This function returns the absolute error estimate for a given step when solving
a problem as that described for function RKF. The input stack looks as
follows:
After running this function, the stack will show the lines:
Thus, this function is used to determine the increment in the solution, ∆y, as
well as the absolute error (error).
The following screen shots show the RPN stack before and after application of
function RKFERR:
These result show that ∆y = 0.827... and error = -1.89...×10

### Function RSBERR

This function performs similarly to RKERR but with the input elements listed for
function RRK. Thus, the input stack for this function will look as follows:
2:
1:
After running the function, the stack will show the lines:
4:
3:
2:
1:
2:
{'x', 'y', 'f(x,y)'}
1:
4:
{'x', 'y', 'f(x,y)'}
3:
2:
1:
{'x', 'y', 'f(x,y)' '∂f/∂x' '∂f/vy' }
{'x', 'y', 'f(x,y)' '∂f/∂x' '∂f/vy' }:
∆x
ε
∆y
error
-6
.
∆x
ε
∆y
error
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