You are here:

Calculus/probability density function

Advertisement

Expert: - 4/11/2008


Question
A machine component has a useful life of 0 to 10 years and the probability density function modeling when it will wear out is f(x) = .42377x/x^2+.9. Find the probability that the component lasts more than 7 years. Thank you.

Answer
The function really should be 0.42377x/(x^2+0.9) - right?

Try u substitution with u = x^2 + 0.9, du = 2x dx and note that the integral of 1/x is ln(x) + C.

Hopefully this answers your question, Zach, but write back for further assistance or questions on another problem.

Calculus

All Answers

Answers by Expert:

Ask Experts

Volunteer

Scotto

Expertise

Any kind of calculus question you want. I also have answered some questions in Physics (mass, momentum, falling bodies), Chemistry (charge, reactions, symbols, molecules), and Biology.

Experience

Experience in the area: I have tutored students in all areas of mathematics for over 25 years. Education/Credentials: BSand MS in Mathematics from Oregon State University, where I completed sophomore course in Physics and Chemistry. I received both degrees with high honors. Awards and Honors: I have passed Actuarial tests 100, 110, and 135.

Publications
Maybe not a publication, but I have respond to well oveer 7,500 questions on the PC. Well over 2,000 of them have been in calculus.

Education/Credentials
I aquired well over 40 hours of upper division courses. This was well over the number that were required. I graduated with honors in both my BS and MS degree from Oregon State University. I was allowed to jump into a few junior level courses my sophomore year.

Awards and Honors
I have been nominated as the expert of the month several times. All of my scores right now are at least a 9.8 average (out of 10).

Past/Present Clients
My past clients have been students at OSU, students at the college in South Seattle, referals from a company, friends and aquantenances, people from my church, and people like you from all over the world.

©2012 About.com, a part of The New York Times Company. All rights reserved.