# Search results

1. ### Central Limiting Theorem?

Homework Statement The amounts of time that a cashier spends processing individual customers' orders are independent random variables with mean 2.5 minutes and standard deviation 2 minutes. a) What is the approximate probability that it will take more than 4 hours to process orders of 100...
2. ### Poisson, Binomial Distributions

Homework Statement The number of claims that an insurance company receives per week is a random variable with the Poisson distribution with parameter λ. The probability that a claim will be accepted as genuine is p, and is independent of other claims. a) What is the probability that no claim...
3. ### Linear Algebra: Spans and Dimensions

Homework Statement Given v1, v2 ... vk and v, let U = span {v1, v2 ... vk} and W = span {v1, v2 ... vk, v}. Show that either dim W = dim U or dim W = 1 + dim U. The Attempt at a Solution I'm not really sure where to start. If I knew that {v1, v2 ... vk} was linearly independent, then it would...
4. ### Linear Algebra: Linear indepency of a set of Polynomials

Homework Statement Let {p, q} be linearly independent polynomials. Show that {p, q, pq} is linearly independent if and only if deg p ≥ 1 and deg q ≥ 1. Homework Equations λ1p + λ2q = 0 ⇔ λ1 = λ2 = 0 The Attempt at a Solution λ1p + λ2q + λ3pq = 0 I know if λ3 = 0, then the coefficients of...
5. ### Linear Algebra: Prove that the set of invertible matrices is a Subspace

Homework Statement Is U = {A| A \in nℝn, A is invertible} a subspace of nℝn, the space of all nxn matrices? The Attempt at a Solution This is easy to prove if you assume the regular operations of vector addition and scalar multiplication. Then the Identity matrix is in the set but 0*I and...
6. ### Differentiating This Function

Somebody want to help with this derivative: y = (7.75x3 + 2250) / 750x I differentiate it with the quotient rule and get: dy/dx = 31x / 1500 - 3 / x2 But that's wrong. It's got a zero around 5 - 6 and the original function has its minimum at (4.03, 1.12). Not sure what I did wrong.
7. ### Help with This Derivative

Does somebody want to help me with differentiating this function: (0.003 + 0.004\sqrt{2})∏r2 + 0.004∏r [(2250 - ∏r3) / 3∏r2)] Originally I tried simplifying it by distributing the 0.004∏r into the fraction, but whenever I did that the two expressions were never equivalent when I checked them...
8. ### Determining Tangent Slope w/Point Not On Curve

How do you determine the equation of all possible tangents to a curve (say, a parabola) that pass through a given point that is not on said curve? This is more of a conceptual question, and it's not homework, so I thought it fit in this forum. I think there might be a question like this on the...
9. ### Stargazing Looking to buy my first telescope

Right so I'm looking to buy my first telescope and rather than start a thread I thought I'd post here. How does this look for a beginner telescope? Keeping in mind its my first and I really only want to look at the moon, some of the closer planets, and maybe some nearby galaxies or nebulae. I am...
10. ### Young's Double Slit Experiment science fair

I plan on trying to recreate a version of Young's double slit experiment for a science fair. All the methods I've found for it recommend using a helium-neon laser. Would a laser pointer or some other cheaper laser work? For the slits my idea is to get a glass microscope slide, paint over it then...
11. ### Electrons Colliding - Totally Confused

Homework Statement Two electrons separated by a large distance are fired directly at each other. The closest approach in this head-on collision is 4.0 * 10-14 m. One electron starts with twice the speed of the other. Assuming there is no deflection from the original path, determine the initial...
12. ### Elastic Collision - two carts

Homework Statement Two carts equipped with spring bumpers on an air track have an elastic collision. The 253-g cart has an initial velocity of 1.80 m/s [N]. The 232-g cart is initially stationary. What is the velocity of each cart after the collision? Homework Equations I know because cart 2...
13. ### Recommended Software Language to Learn?

I am just finishing up grade 11 and thought it would be worthwhile to learn a programming language over the summer. However, I'm unsure which language I would do best to learn. I can already code in Turing, HTML, and Java. I am most likely going to pursue an education in science or engineering...

Well, I'm in grade 11, I think the major for me is Aerospace engineering. Unfortunately, there are only two schools in Canada that offer a dedicated aerospace engineering program, and neither of them are extremely well-regarded in terms of academics (as I understand). Which leads me to my...
15. ### Calculating Constant speed of an Elevator Rising

Homework Statement The motor for an elevator can produce 14kW of power. The elevator has a mass of 1100 kg, including its contents. At what constant speed will the elevator rise? Homework Equations I'm not really sure. Probably Gravitational potential = mgh. Kinetic energy = 1/2mv^2...