Related Rates: Particle Moving Along y=x^1/3, x=8, Theta Approx. 0.24 Rad

In summary, a particle is moving along the graph of y=x^1/3 and x is increasing at a rate of 3 cm/s. The question asks for the rate of change of the angle of inclination, theta, when x=8. To find this, we need to find the derivative of theta by writing it as a function of x and plugging in x=8 to get a numerical value.
  • #1
NIZBIT
69
0
Code:
A particle is moving along the graph of y=x^1/3.  
Suppose x is increasing at the rate of 3 cm/s.  
At what rate is the angle of inclination, theta, changing when x=8?  
[Hint: when x=8, theta approx. 0.24 rad]
I'm stuck on problem. I know x=8, y=2 and the hyp=2.87. They want the derivative of theta so am I supposed to take the derivative of theta=0.24?
 
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  • #2
No, you want to find some function that defines theta, and take the derivative of that.
 
  • #3
NIZBIT said:
Code:
A particle is moving along the graph of y=x^1/3.  
Suppose x is increasing at the rate of 3 cm/s.  
At what rate is the angle of inclination, theta, changing when x=8?  
[Hint: when x=8, theta approx. 0.24 rad]
I'm stuck on problem. I know x=8, y=2 and the hyp=2.87. They want the derivative of theta so am I supposed to take the derivative of theta=0.24?
Well, the derivative of a constant (0.24) is 0 so that wouldn't do a whole lot of good would it? :wink: It's a lot more helpful to find the derivative of a function rather than a number! Draw a picture, showing the "angle of inclination" and write theta as a function of x. Then find the derivative of that function with respect to x. (Do you remember that the derivative of a function is the tangent of the angle the tangent line to the graph makes with the x-axis?)
 
  • #4
yo.gif

Is this correct? Or am I completely off my rocker?:frown:
 
  • #5
You're off your rocker. :biggrin:

Try following these steps:

1.) Draw a graph of f(x)=x1/3 vs. x.

2.) Consider an arbitrary point on the curve: (x,y)=(x,x1/3)

3.) Draw a line segment from the origin to (x,y) and drop a vertical line segment down from (x,y) to the x-axis. You now have a right triangle.

4.) The angle made by the line segment (the one connecting (0,0) to (x,y)) and the x-axis is the angle of inclination. Write down an expression for it in terms of x.

Try that and let's see what you come up with.
 
  • #6
yup.gif

Is this right?
 
  • #7
So far so good, but you're supposed to plug in x=8 and get a number for [itex]d\theta/dt[/itex].
 
  • #8
Sweet! Thanks to all for the help!
 

FAQ: Related Rates: Particle Moving Along y=x^1/3, x=8, Theta Approx. 0.24 Rad

What is a particle moving along y=x^1/3?

A particle moving along y=x^1/3 means that the position of the particle is determined by the function y=x^1/3, where x is the independent variable and y is the dependent variable.

What is the significance of x=8 in this scenario?

The equation x=8 means that the particle is moving along the line x=8, which is a vertical line passing through the point (8,0). This indicates that the particle is constrained to move only along this line.

What does it mean for theta to be approximately 0.24 rad?

This means that the angle of rotation for the particle is approximately 0.24 radians, where 1 radian is equivalent to about 57.3 degrees. This angle is used to calculate the rate of change of the particle's position.

How is the rate of change of the particle's position calculated in this scenario?

The rate of change of the particle's position can be calculated using the formula dy/dx = (dy/dt) / (dx/dt), where dy/dt and dx/dt are the rates of change of y and x respectively with respect to time.

What is the relationship between the rates of change of x and y in this scenario?

Since the particle is moving along the line x=8, the rate of change of x (dx/dt) is constant. However, the rate of change of y (dy/dt) will vary depending on the angle of rotation (theta) and can be calculated using trigonometric functions such as sine and cosine.

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