3.設(shè)函數(shù)f(x)在x=0處連續(xù)，g(x)在x=0處不連續(xù)，則在=0處

• A、f(x)g(x)連續(xù)
  
  

• B、f(x)g(x)不連續(xù)
  
  

• C、f(x)+g(x)連續(xù)
  
  

• D、f(x)+g(x)不連續(xù)
  
  

13.設(shè)y=3x2+ln3,則y'=_____.

7.若函數(shù)f(x)的導(dǎo)數(shù)f'(x)=-x+1，則

• A、f(x)在(-∞,+∞)單調(diào)遞減
  
  

• B、f(x)在(-∞,+∞)單調(diào)遞增
  
  

• C、f(x)在(-∞,1) 單調(diào)遞增
  
  

• D、f(x)在(1,+∞)單調(diào)遞增