matlab中 simple函数

　　我运行没问题呀，可能是精简版功能不齐全，要不你试试加上syms x

• >> y=sym('2*sin(x)*cos(x)');
  >> y
  y =
  2*cos(x)*sin(x)
  >> simple(y)
  simplify:
  sin(2*x)
  radsimp:
  2*cos(x)*sin(x)
  simplify(100):
  sin(2*x)
  combine(sincos):
  sin(2*x)
  combine(sinhcosh):
  2*cos(x)*sin(x)
  combine(ln):
  2*cos(x)*sin(x)
  factor:
  2*cos(x)*sin(x)
  expand:
  2*cos(x)*sin(x)
  combine:
  2*cos(x)*sin(x)
  rewrite(exp):
  2*((1/exp(x*i))/2 + exp(x*i)/2)*(((1/exp(x*i))*i)/2 - (exp(x*i)*i)/2)
  rewrite(sincos):
  2*cos(x)*sin(x)
  rewrite(sinhcosh):
  2*cosh(-x*i)*sinh(-x*i)*i
  rewrite(tan):
  -(4*tan(x/2)*(tan(x/2)^2 - 1))/(tan(x/2)^2 + 1)^2
  mwcos2sin:
  -2*sin(x)*(2*sin(x/2)^2 - 1)
  collect(x):
  2*cos(x)*sin(x)
  ans =
  sin(2*x)

应加上syms x

>> syms x;
y=sym('2*sin(x)*cos(x)');
y=simple(y)

y =

sin(2*x)