Learning Guide Learning Guide

162 • Chapter 5: Evaluation and SimplificationConverting Between Equivalent FormsYou can write many mathematical functions in several equivalent forms.For example, you can express sin(x) in terms of the exponential function.The convert command can perform this and many other types ofconversions. For more information, refer to ?convert.> convert( sin(x), exp );−12 I (e(x I) − 1e> convert( cot(x), sincos );cos(x)sin(x)(x I))> convert( arccos(x), ln );−I ln(x + √ −x 2 + 1 I)> convert( binomial(n,k), factorial );n!k! (n − k)!The parfrac argument indicates partial fractions.> convert( (x^5+1) / (x^4-x^2), parfrac, x );x + 1x − 1 − 1 x 2You can also use convert to find a fractional approximation to afloating-point number.> convert( .3284879342, rational );1961559713Note that conversions are not necessarily mutually inverse.> convert( tan(x), exp );