Set the accuracy of all numbers in an expression to 20:

Convert from a machine number to an arbitrary-precision number with accuracy 32:

Set the accuracy of a complex number:

Convert approximate numbers to exact rational numbers:

The result has trailing zeros once any hidden digits are exposed:

SetAccuracy does not affect exact powers:

This allows you to, for example, change the accuracy of polynomial coefficients:

Inexact powers are modified:

Special rules may apply to data objects:

For an InterpolatingFunction object, SetAccuracy changes the appropriate data only:

It works as an approximate function, but with arithmetic appropriate for the modified data:

Find the roundoff error in evaluating an expression with machine numbers:

This dominates the approximation error since the increment is so small:

SetAccuracy just sets the precision of numbers, while N works adaptively:

Since N works adaptively, the result has the requested accuracy of 20:

Use SetAccuracy:

The accuracy is less than 20 because of the way the exponential function magnifies the result:

SetAccuracy effectively evaluates Exp with argument 10 to accuracy 20:

For nonzero numbers , SetAccuracy[x,a] is equivalent to SetPrecision[x,a+e]:

e is given by RealExponent: