Translation of a Conic Section

Key Questions

  • When translating a graph to the left or to the right, it means moving the entire graph to the left or to the right of its current location, which is usually relative to (0,0)

    For example, let's say you have a circle centered at (0,0) with radius 2. Its standard equation would be

    x2+y2=4

    Now, let's say we translate the circle 5 units to the left. Your circle will now be centered at (-5, 0) with the radius still equal to 2. Its new standard equation would be

    (x+5)2+y2=0


    This is also true for linear equations.
    For example, let's say you have a line with slope 1 with the x-intercept equal to 0. Its equation will be

    y=x

    When we translate the line 3 units to the right, its slope will remain the same, but its x-intercept will now be 3. Its new equation will be

    y=x5

  • Translations are simply horizontal and/or vertical shifts. So, y=x2 is shifted 2 units down from y=x, while y=x2 is shifted 2 units right of y=x.

    y=x:
    graph{sqrtx [-10, 10, -5, 5]}

    y=x2:
    graph{sqrtx - 2 [-10, 10, -5, 5]}

    y=x2:
    graph{sqrt(x-2) [-10, 10, -5, 5]}

    y=x22:
    graph{sqrt(x-2) - 2 [-10, 10, -5, 5]}

  • You can translate any function, y=f(x) using:

    y=f(xh)+k or
    yk=f(xh)

    If h is positive, the graph will translate to the right.
    If h is negative, the graph will translate to the left.
    If k is positive, the graph will translate up.
    If k is negative, the graph will translate down.

    Here is an example:

    f(x)=x2+2x

    If we want to translate this up 4 units, then we have:

    y=f(x)+4
    y=x2+2x+4
    enter image source here

    If we have a different example:

    f(x)=1x
    y=f(x)+4
    y=1x+4
    enter image source here
    It still works!

Questions