A PDF formed from a multivariate function

Or solve it analytically.In summary, we have a bivariate function ##f(x,y)=y\sqrt{(x-2)^2-y}## over the domain ##[0,b]##, where ##b## is the x-intercept. From this, we can form a probability density function ##p(x)=\int_{-a}^a (f(x,a-y)-f(y,ax))dy##. To determine the values of ##a## and ##b##, we need to substitute the actual values of ##f(x,a-y)## and ##f(y,ax)## into ##p(x)## and integrate. However, this may result in an "insufficient memory" error, so
  • #1
Saracen Rue
150
10

Homework Statement


A probability density function, ##p\left(x\right)=\int _{-a}^a\left(f\left(x,\left(a-y\right)\right)-f\left(y,ax\right)\right)dy##, can be formed from the bivariate function ##f\left(x,y\right)=y\sqrt{\left(x-2\right)^2-y}## over the domain ##[0,b]## - where ##b## is the coordinate of the x-intercept.

(a) Determine the values of ##a## and ##b## correct to 5 decimal places
(b) Calculate the expected value, variance and standard deviation of ##p(x)## correct to 4 decimal places
(c) Find the percentage probability of the continuous random variable ##X## being withing ##|a|## standard deviations either side of the mean​

Homework Equations


Knowledge or probability density functions, including integral applications.

The Attempt at a Solution


Well I know that I need to substitute the actual values for ##f\left(x,\left(a-y\right)\right)## and ##f\left(y,ax\right)## into ##p(x)## to be able to integrate ##\int _{-a}^a\left(f\left(x,\left(a-y\right)\right)-f\left(y,ax\right)\right)dy##, and then I'd need to solve ##int_0^b p(x)dx for b and then use that to solve for a. However, when I attempt to do this on my calculator I receive and error message. Does anyone know how I could do this?
 
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  • #3
mfb said:
Which error message do you get?

I receive the message: "ERROR: Insufficient Memory"
 
  • #4
Maybe you can simplify the function a bit, or use a better calculator.
 

What is a PDF formed from a multivariate function?

A PDF (Probability Density Function) formed from a multivariate function is a mathematical representation of the probability distribution of multiple variables. It shows the likelihood of a set of variables taking on certain values.

How is a PDF formed from a multivariate function calculated?

A PDF formed from a multivariate function is calculated by taking the derivative of the multivariate function with respect to each variable and then multiplying them together. This results in a joint probability density function that takes into account the relationships between the variables.

What is the purpose of using a PDF formed from a multivariate function?

A PDF formed from a multivariate function is used to understand and analyze the relationships between multiple variables. It allows for the calculation of probabilities for specific combinations of values for the variables, which can be useful in making predictions or decisions.

What types of multivariate functions can be used to form a PDF?

Any multivariate function can be used to form a PDF, as long as it meets the criteria of being continuous and differentiable. Commonly used functions include the normal distribution, beta distribution, and exponential distribution.

How is a PDF formed from a multivariate function represented graphically?

A PDF formed from a multivariate function is typically represented graphically as a surface plot, with the axes representing the variables and the height of the surface representing the probability density. Contour plots can also be used to show the probability density at specific values of the variables.

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