2. A curve has equation y = x2 – 2x - 3. A point moves along the curve in such a way that at P
the y coordinate is increasing at 4 units per second and the x coordinate is increasing at 6
units per second. Find the x coordinate of P.
[3]

Respuesta :

Answer:

The x coordinate of P is [tex]\frac{4}{3}[/tex].

Step-by-step explanation:

Let is find the rate of change of the equation in time, which consists in a composite differentiation. That is:

[tex]\frac{dy}{dt} = 2\cdot x \cdot \frac{dx}{dt} -2\cdot \frac{dx}{dt}[/tex]

According to the statement of the problem, these variables are known:

[tex]\frac{dx}{dt} = 6[/tex] and [tex]\frac{dy}{dt} = 4[/tex]

Hence, the x coordinate of P is found by direct substitution:

[tex]4 = 2\cdot x \cdot (6)-2\cdot (6)[/tex]

[tex]4 = 12\cdot x -12[/tex]

[tex]x = \frac{4}{3}[/tex]

The x coordinate of P is [tex]\frac{4}{3}[/tex].