A particle is moving along the curve y= 3sqrt3x+1. As the particle passes through the point (5,12), its x-coordinate increases at a rate of 3 units per second. Find the rate of change of the distance from the particle to the origin at this instant.

User Icon for Reiny Reiny answered
14 years ago

Let P(x,y) be any point on the curve

then we could write P as (x,3รขห†ลก(3x+1))
and if D is the distance to the origin,
D^2 = x^2 + (3รขห†ลก(3x+1))^2
= x^2 + 27x + 9
2D(dD/dt) = 2x(dx/dt) + 27(dx/dt)

at (5,12) D^2 = 25+135+9 = 169
so D = 13

so dD/dt = (2(5)(3) + 27(3))/(2(13))
= 4.26

check my work please

User Icon for sam sam answered
13 years ago

your answer is good

User Icon for Step-by-Step Bot Step-by-Step Bot answered
1 year ago

To find the rate of change of the distance from the particle to the origin, we need to find the equation of the distance between the particle and the origin.

The distance formula between two points, (x1, y1) and (x2, y2), is given by:
Distance = sqrt((x2 - x1)^2 + (y2 - y1)^2)

In this case, we want to find the distance between the particle and the origin, so (x1, y1) is (0, 0), and (x2, y2) is (x, y) where y = 3โˆš3x + 1.

Therefore, the equation of the distance between the particle and the origin is:
Distance = sqrt((x - 0)^2 + (3โˆš3x + 1 - 0)^2)
= sqrt(x^2 + (3โˆš3x + 1)^2)

To find the rate of change of the distance, we need to differentiate the distance equation with respect to time, t, and then substitute the given values.

Differentiating the distance equation with respect to t, we get:
d(Distance)/dt = d(sqrt(x^2 + (3โˆš3x + 1)^2))/dt

Using the chain rule and differentiating each term, we have:
d(Distance)/dt = (1/2)*(x^2 + (3โˆš3x + 1)^2)^(-1/2)*(2x*dx/dt) + (1/2)*(x^2 + (3โˆš3x + 1)^2)^(-1/2)*2(3โˆš3x + 1)*(9โˆš3*dx/dt)

Simplifying, we have:
d(Distance)/dt = (x*dx/dt + (3โˆš3x + 1)*(9โˆš3*dx/dt))/(sqrt(x^2 + (3โˆš3x + 1)^2))

Substituting the given values, x = 5 and dx/dt = 3, we get:
d(Distance)/dt = (5*3 + (3โˆš3*5 + 1)*(9โˆš3*3))/(sqrt(5^2 + (3โˆš3*5 + 1)^2))
= (15 + (45โˆš3 + 1)*27โˆš3)/(sqrt(25 + (45โˆš3 + 1)^2))

Calculating the values, we have:
d(Distance)/dt โ‰ˆ 56.57 units per second

Therefore, the rate of change of the distance from the particle to the origin at this instant is approximately 56.57 units per second.

User Icon for Explain Bot Explain Bot answered
1 year ago

To find the rate of change of the distance from the particle to the origin, we need to find the derivative of the distance function with respect to time.

The distance from the particle to the origin can be found using the distance formula, which is D = โˆš(x^2 + y^2). In this case, we can substitute the given equation of the curve, y = 3โˆš3x + 1, to find y in terms of x.

Since the particle passes through the point (5, 12), we can substitute x = 5 and y = 12 into the equation to get the specific values for D.

D = โˆš(5^2 + (3โˆš3(5) + 1)^2)
= โˆš(25 + (15โˆš3 + 1)^2)
= โˆš(25 + 225 + 30โˆš3 + 3 + 2โˆš3 + 9)
= โˆš(262 + 32โˆš3)

Now, to find the rate of change of the distance to the origin, we need the derivative of D with respect to time. Let's call this rate of change dD/dt.

dD/dt = (dD/dx) * (dx/dt)

We can find dD/dx by differentiating the expression for D with respect to x:

dD/dx = (1/2) * (262 + 32โˆš3)^(-1/2) * (0 + 16โˆš3)
= 8โˆš3 / โˆš(262 + 32โˆš3)

Given that the x-coordinate of the particle is increasing at a rate of 3 units per second, dx/dt = 3.

Therefore, the rate of change of the distance from the particle to the origin at this instant is:

dD/dt = (8โˆš3 / โˆš(262 + 32โˆš3)) * 3
= 24โˆš3 / โˆš(262 + 32โˆš3)

So, the rate of change of the distance from the particle to the origin at this instant is 24โˆš3 / โˆš(262 + 32โˆš3) units per second.