수식 3: 0 less than "y" less than "f" left parenthesis, "x" , right parenthesis left brace, 0 less than or equal to "x" less than or equal to 2 fifths , right brace0<y<fx0≤x≤25
3
수식 4: Start integral from 0 to 2 fifths , end integral, "f" left parenthesis, "x" , right parenthesis "d" "x"∫250fxdx