The area of the region bounded by the parabola
, the tangent line at
, and the x-axis is
square units.
To find the area of the region bounded by the parabola
, the tangent line at
, and the x-axis, you'll need to find the x-coordinate where the tangent line intersects the parabola. Then, you can set up the integral to find the area between these curves.
First, let's find the equation of the tangent line to the parabola
at the point
. The derivative of
is
, which gives the slope of the tangent line at any point
.
At
, the slope of the tangent line is
. The equation of the tangent line in point-slope form is:

where
is the slope and
is the point on the line.
Using
and
:
![\[y - 27 = 18(x - 3)\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/p7frtt2rswgb8zi0eugl3xv11b3lj0zleq.png)
![\[y - 27 = 18x - 54\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/a5xat4mqcovujdvfxdeehn3pszq7ozjom2.png)
![\[y = 18x - 27\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/van1127u4weazksw7kxiip4wiltvv8dbxd.png)
To find the x-coordinate where the tangent line intersects the parabola, set the equations of the parabola and the tangent line equal to each other:
![\[3x^2 = 18x - 27\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/e60spkdwxj1vumiacrtfceyb9vnsqih8zm.png)
![\[3x^2 - 18x + 27 = 0\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/npcou8hgm8alne1vhpnnvnckj70r9dfwea.png)
![\[x^2 - 6x + 9 = 0\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/h7gk3bynjl6u7t163zqg8enbvv2kuupr09.png)

This gives us a repeated root of
, meaning the tangent line intersects the parabola at
.
Now, to find the area bounded by these curves, integrate the difference between the curves from
to
. The curves are
(the parabola) and
(the x-axis).
The area
is given by:
![\[A = \int_0^3 (3x^2 - 0) \, dx\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/5e8e940tj6j0f8rm8j0vugqeerozchxi6m.png)
![\[A = \int_0^3 3x^2 \, dx\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/cc0oa8e842hahzujuir7zjugcw03baxfi6.png)
![\[A = \left[x^3\right]_0^3\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/tmrh4cuqxm6q5o0li60cibc2r291dtpzh4.png)
![\[A = 3^3 - 0^3\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/h5xgtvcnwp2h1y81dvjfzfozgs5cfv8km0.png)
![\[A = 27\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/dd4eclnwd25c0jcu0vngs8kyj3soipno6x.png)
Therefore, the answer is
square units.