Learning Guide Learning Guide

12 • Chapter 2: Mathematics with Maple: the Basicsset of numbers with twenty accurate digits. An exact analytical descriptioncan also determine the behavior of a function when extrapolating toregions for which no data exists.The evalf command converts an exact numerical expression to afloating-point number.> evalf(Pi);3.141592654By default, Maple calculates the result using ten digits of accuracy,but you can specify any number of digits. Simply indicate the numberafter the numerical expression, using the following notation.> evalf(Pi, 200);3.1415926535897932384626433832795028841\97169399375105820974944592307816406286\20899862803482534211706798214808651328\23066470938446095505822317253594081284\81117450284102701938521105559644622948\9549303820You can also force Maple to do all its computations with floatingpointapproximations by including at least one floating-point number ineach expression. Floats are “contagious”: if an expression contains evenone floating-point number, Maple evaluates the entire expression usingfloating-point arithmetic.> 1/3 + 1/4 + 1/5.3;0.7720125786> sin(0.2);0.1986693308While the optional second argument to evalf controls the numberof floating-point digits for that particular calculation, the special variableDigits sets the number of floating-point digits for all subsequentcalculations.