• 已知f(x)=x2-53x+196+|x2-53x+196|,则f(1)+f(2)+…+f(50)= .试题及答案-单选题-云返教育

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      已知f(x)=x2-53x+196+|x2-53x+196|,则f(1)+f(2)+…+f(50)=         

      试题解答


      660
      解:由x2-53x+196>0得 x>49或x<4,
      ∴当4≤x≤49时,x
      2-53x+196≤0,
      ∴当4≤x≤49时,f(x)=x
      2-53x+196+|x2-53x+196|=x2-53x+196-(x2-53x+196)=0,
      当x>49或x<4时,f(x)=x
      2-53x+196+|x2-53x+196|=x2-53x+196+(x2-53x+196)=2(x2-53x+196),
      ∴f(1)+f(2)+…+f(50)=f(1)+f(2)+f(3)+f(50)
      ∵f(1)=2(1-53+196)=2×144=288,
      f(2)=2(4-53×2+196)=2×94=188,
      f(3)=2(9-53×3+196)=2×46=92,
      f(50)=2(50
      2-53×50+196)=2×46=92,
      ∴f(1)+f(2)+…+f(50)=f(1)+f(2)+f(3)+f(50)=288+188+92+92=660.
      故答案为:660.
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