## WeBWorK Main Forum

### display precision in Solution computation

by Joel Trussell -
Number of replies: 2
IN the TEXT part of the problem the values display with 4-6 decimals, Likewise in the answer check. However, when we display the solution, the results display 15 digits, e.g.
B=7/52=0.134615384615385." role="presentation">B=7/52=0.134615384615385.
the code is

How do I get this display to limit the number of decimals?
The code is
$PAR To find the particular solution, we know the form of the particular solution is the same as that of the driving function. In this case, it is a constant, $$v_p(t) = B$$. We differentiate the particular solution as needed and substitute into the differential equation. Since $$\dot{v}_p(t) = \ddot{v}_p(t) = 0$$, we have the equation, $$c v_p(t) = c B = A.$$ We solve for $$B$$ to obtain $$B = A/c = B.$$$PAR
B=7/52=0.134615384615385." role="presentation">

### Re: display precision in Solution computation

by Alex Jordan -
If you see that many decimals, you are probably displaying a "pure" perl scalar real.

If you see something trimmed to about 6 decimals, you are probably seeing a MathObject Real.

My guess is that if you look closely at the two variables used in the two places, they are not actually the same thing. Or there is a reassignment of that variable in between.

Here is some example code:

$b = 7/52; #$b is now a perl sclalar real with value 0.134615384615385...
# It will display as 0.134615384615385

$B = Compute(7/52); #$B is a MathObject.
# Compute will recognize to make it a Real, as opposed to say a Formula.
# You could achieve essentially the same thing with:
# $B = Real(7/52); #$B = Real("7/52");
# $B = Real($b);
# $B = Real("$b");
# $B = Compute("7/52"); #$B = Compute($b); #$B = Compute("$b"); # although some of these would store a little extra information than others. # While the information 0.134615384615385... is still stored within$B,
# the default display controls for MathObjects
# would only display this as 0.134615