>>[n, d]=numden(f% extract the numerator and denominator 前二个表达式得到期望结果 >>g=3/2 x2+2/3 x-3/5% rationalize and extract the parts 3/2*x^2+2/3*x-3/5 >>[n, d]=numden(g 45*x^2+20*x-18 >>h='(x2+3)/(2*x-1)+3*X/(x-1)% the sum of rational polynomials (x^2+3)/(2*x-1)+3*x/(x-1) >>n, d]=numden(h)% rationalize and extract x^3+5*x^2-3 在提取各部分之前,这二个表达式g和h被有理化,并变换成具有分子和分母的一个简单表 达式 >>k=sym(3/2,(2*x+1)/3: 4/x2, 3*x+4 ) try a symbolic array 3/2,(2*x+1)/3] [4Xx^2,3*x+4]>> [n，d]=numden(f) % extract the numerator and denominator n= a*x^2 d= b-x 前二个表达式得到期望结果。 >> g= ' 3/2*x^2+2/3*x-3/5 ' % rationalize and extract the parts g= 3/2*x^2+2/3*x-3/5 >> [n，d]=numden(g) n= 45*x^2+20*x-18 d= 30 >> h= ' (x^2+3)/(2*x-1)+3*x/(x-1) ' % the sum of rational polynomials h= (x^2+3)/(2*x-1)+3*x/(x-1) >> [n，d]=numden(h) % rationalize and extract n= x^3+5*x^2-3 d= (2*x-1)*(x-1) 在提取各部分之前，这二个表达式g和h被有理化，并变换成具有分子和分母的一个简单表 达式。 >> k=sym( ' [3/2，(2*x+1)/3；4/x^2，3*x+4] ' ) % try a symbolic array k= [ 3/2，(2*x+1)/3] [4/x^2， 3*x+4] >> [n，d]=numden(k) n= [3， 2*x+1] [4， 3*x+4] d=