Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Graphing slope of tangent

  1. Jan 25, 2009 #1
    1. The problem statement, all variables and given/known data
    Find an equation for the tangent to the curve at the given point. Then sketch the curve and tangent together


    2. Relevant equations
    y=3-x^2 (-1,2)


    3. The attempt at a solution

    slope =

    f(x + h) + f(x) / h

    f(-1 + h) + 2 / h

    3- (-x + h)^2 + 2 / h

    3 - 1 + 2h + H^2 + 2 / h

    2h + h^2 / h

    = 2 + h
    = 2

    slope is 2

    y - y1 = m(x - x1)

    y - 2 = 2 (x + 1)
    y = 2x + 4 = equation


    Ok so I have no idea how to graph a tangent, can someone tell me how you graph this? I know how to sketch the graph 3- x^2 since it is a ^2 function it is u shaped, flipped on the x axis moved up three on the y. I know the tangent obviously passes through -1, 2 but how do I graph the rest? I know y intercept for tangent is 4, but where does it pass through x at? I am a little rusty
     
  2. jcsd
  3. Jan 25, 2009 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Do you mean where does it cross the x-axis? It does that when y=0 in the equation y=2x+4. Solve for x. You are rusty. It's just graphing a straight line.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook