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Plotting Supply & Demand CurveHey everyone, I'm new here, would love some help on this problem. *Note: At market equilibrium, we have Demand = SupplyCode: `The supply and demand functions for a good are given, respectively, by` (a) q = 2p + 10 -----(1) p(q + 4) = 60 ---(2) substitute (1) into (2) p ( (2p +10) + 4) = 60 2p^2 + 14p - 60 = 0 p^2 + 7p - 30 = 0 (p + 10) (p - 3) = 0 p = -10 or 3 But, price and quantity equilibrium can't be a negative, so p = 3. That's part (a) solved. Now I have no idea how to transition to part (b), help would be appreciated, thanks! |

Re: Plotting Supply & Demand Curve1 Attachment(s) Since this does not involve the calculus, I have moved the topic to the appropriate forum. Here is a plot of the two functions on the same graph: [attachment=0:2jyfbf79]supplydemand.jpg[/attachment:2jyfbf79] |

Re: Plotting Supply & Demand CurveHow do you derive the coordinates in relation to the supply and demand equation? Given that we know the market equilibrium falls on the (3,16) coordinates. |

Re: Plotting Supply & Demand CurveIf we let p be the independent variable, then the first equation:is a line given in slope-intercept form. We know it will have the point (0,10) and since the slope is 2, it will also have the point (1,12). Then we just run a line through these two points. If we solve the second equation for q, we find:We see that this is a hyperbolic curve with vertical asymptote and horizontal asymptote . We also know it contains the point (3,16). It also has the p-intercept at (15,0). This is enough information to sketch the curve. |

Re: Plotting Supply & Demand CurveThanks Mark. But what if I want p to be on the y-axis and q on the x-axis instead? And wouldn't the supply curve be: q = 2p +10 if q = 0, 0 = 2p+10 p = -5 (0 , -5) cutting through (16, 3) instead? |

Re: Plotting Supply & Demand Curve1 Attachment(s) Yes, you would find the point (-5,0) to be on the line if we extend it to the left. If we wish for q to be the independent variable instead, then we solve both equations for p:(1) (2) [attachment=0:5pfdprrb]supplydemand2.jpg[/attachment:5pfdprrb] |

Re: Plotting Supply & Demand CurveSo, if I want to make a particular variable as the independent value, I'll just assume that it equals to 0? *ps: What kind of software are you using to input the equations and graphs on your answers? I noticed that it's not text based when I tried to highlight it. |

Re: Plotting Supply & Demand CurveIf you want a particular variable to be independent, then solve for the other variable. I am using the site http://www.wolframalpha.com/ to plot the graph. For the second graph I used the command: y=(x-10)/2,y=60/(x+4) for x = 0 to 20 Then, I hit [ALT][PRT SCRN] to save a screenshot to the clipboard, opened MS-Paint and copied, cropped and saved the image, then attached it. |

Re: Plotting Supply & Demand CurveGot it, thank you so much Mark! You've been a great help. |

Re: Plotting Supply & Demand CurveGlad to help, and welcome to the forum! :mrgreen: |

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