简单使用matlab求值

y=x^3+〖(x-0.98)〗^2⁄〖(x+1.25)〗^3 -5(x+1/x),x=2,x=4 时的值。
clear;syms x y;x=2;y=x^3+(x-0.98)^2/(x+1.25)^3-5*(x+1/x)

y =

   -4.4697
cos⁡60°-∛(9-√2)
cos(60*pi/180)-(9-2^0.5)^(1/3)

ans =

   -1.4649
	a=3,A=4,b=a^2,B=b^2-1,c=a+A-2B,C=a+B+2c
求：C
a=3,A=4,b=a^2,B=b^2-1,c=a+A-2*B,C=a+B+2*c

a =

     3


A =

     4


b =

     9


B =

    80


c =

  -153


C =

  -223