Yahoo 知識+ 將於 2021 年 5 月 4 日 (美國東岸時間) 停止服務,而 Yahoo 知識+ 網站現已轉為僅限瀏覽模式。其他 Yahoo 資產或服務,或你的 Yahoo 帳戶將不會有任何變更。你可以在此服務中心網頁進一步了解 Yahoo 知識+ 停止服務的事宜,以及了解如何下載你的資料。

Lv 55,388 points

Toy Fox Terrier

最佳解答15%
解答1,251
  • Find Pr[5X - 4Y > 40], given that they are indep&normal, and...?

    that mean-x=18, mean-y=14, std dev-x=3, std dev-y =2.

    I'm not sure how to go about solving this problem?

    2 個解答Mathematics10 年前
  • Poisson probability question?

    Given a Poisson process w/ lambda=0.8 (events per week). Find the probability that the first event will happen during the second or third week.

    How do I go about doing this?

    2 個解答Mathematics10 年前
  • How to do summation of k^2 + 1?

    How would I get the formula to find the summation of (k+1) for k=0...n? (So it would be 1 + 3 + 5...n^2 + 1)?

    1 個解答Mathematics10 年前
  • Help with summation problems?

    How would you find a formula for the series n, (n-1), (n-2)...1? Thanks!

    3 個解答Mathematics10 年前
  • Recommend a new game?

    I'm looking for a new computer game (needs to be Mac compatible...)

    In the past I've liked games like Sims, Zoo Tycoon, World of Warcraft, Harvest Moon...

    Games where you just shoot and kill stuff bores me...any suggestions?

    6 個解答Video & Online Games10 年前
  • Is it possible to break your foot without realizing it?

    So the flat part on the top of my foot, the region before my big toe and the two next to it, has been painful since monday. I felt slight discomfort when I was on the elliptical, just ignored it and finished my workout. It didn't hurt at all until later that day when I tried to stand up from the table when we were at dinner - all the sudden it was extremely painful and I couldn't walk on it.

    I figured I just tweaked it exercising, and it would be fine in a day or so, but its actually gotten worse (throbbing pain even when at rest). No bruising, but visibly swollen and painful to the touch. I have to walk on the outside of my foot so now my ankle is strained, too, lol.

    I've got a drs appt on thursday, but I'm wondering what I possibly could have done to it?!? I feel like if I had actually broken it I would have felt a specific painful event. Could it just be from overuse (I run/elliptical 7 days a week, 30-60 mins since, every day since January)? I know nothing about feet injuries, are there kinds of injuries you can get like this that aren't breakages?

    1 個解答Injuries1 十年前
  • Diarrhea after eating ice cream?

    I get a major upset stomach after eating only a small amount of ice cream - just a small spoonful will set me over the edge. I don't think I'm lactose intolerant, though, because I eat yogurt daily without a problem. Any ideas what this could be? Is ice cream just too rich?

    2 個解答Other - General Health Care1 十年前
  • What bra size am I really?

    I'm really confused about my bra size :s I usually wear a 34DD but I've lost weight and they dont fight right.

    At Victorias Secret the woman at front told me I was a 36B, but then they measured me again later and said I was definitely 34DD, even though the waist band is way too big! I tried the 32DD but the cups were too small and everything was just narrow. 34D, the cups too small, band too big.

    I went to Nordstroms and the woman there measured me and said I was a 32F. Then some of the online calculators say I'm like a 30G??

    I'm trying to buy a sports bra online and have no idea what size to get, because I've been told just about everything.

    My ribcage is 28", my bust is 34-35".

    Thoughts on what size I should buy?

    2 個解答Fashion & Accessories1 十年前
  • Havent had period since January...should I be concerned?

    Hi, I'm 18 and I last had my period back in January (definitely not pregnant). I've always been regular before this. However, I've also lost about 25 lbs since Jan, and I've read that weight loss can disrupt these things. Should I be concerned/see a doctor (since I'm pretty sure I know the reason why)?

    3 個解答Women's Health1 十年前
  • Help converting integral from coordinate to polar?

    coordinate: ∫∫sin(x2+y2)dA over the region 16<=x^2+y^2<=64

    convert to polar coordinates and solve.

    I think the integrand should be rsin(r^2)drdtheta, but I'm stuck on the limits of integration...help?

    2 個解答Mathematics1 十年前
  • Read Write Locks question?

    I'm trying to implement read/write locks into my class to replace synchronization on methods.

    My question is...will I only need to add read/write locks onto methods that were synchronized? Or is it possible that some methods, that were unsynchronized when synchronization was the lock method I was using, may require read/writers?

    Thanks, hope this makes sense

    1 個解答Programming & Design1 十年前
  • Integration for volume of elliptical parabaloid?

    solve for volume under the elliptical paraboloid z=2x^2+6y^2 and over the rectangle R=[−5,5]x[−2,2].

    (its the rectangle part thats really confusing me, I get 296/3)

    2 個解答Mathematics1 十年前
  • Double integral question?

    Solve the double integral I=SSd (xy) dA where d is a triangle with vertices (0,0)(5,0)(0,3)

    S is supposed to be an integral sign lol...

    I keep getting 28.125 but thats wrong...

    1 個解答Mathematics1 十年前
  • Min. distance from point to parabaloid?

    point = (1,1,14), paraboloid z=x^2 + y^2. find the min distance.

    I used lagrange multipliers and got -1 for the multiplier, and got the distance to be sqrt(.75) but this is wrong. help?

    1 個解答Mathematics1 十年前
  • Taylor series problem?

    : Find the second-order Taylor polynomial for f(x,y)=5yx^2 + 4xy^3 at the point (1,2)

    (I get 42 + 52(x-1) + 80(y-2) + 10(x-1)^2 + 58(x-1)(y-2) + 23(y-2)^2 but thats wrong...)

    Thanks!

    1 個解答Mathematics1 十年前
  • Multivariable Taylor Series?

    Find the second-order Taylor polynomial for f(x,y)=5yx^2 + 4xy^3 at the point (1,2)

    (I keep getting 42 + 52(x-1) + 80(y-2) + 10(x-1)^2 + 58(x-1)(y-2) + 23(y-2)^2 but thats wrong...)

    1 個解答Mathematics1 十年前
  • Level surfaces of multivariable equations?

    Hi, if you look at the level surfaces of the equation g(xyz)=e^-(x^2+(y−1)^2+z^2)

    1. Pick a level surface that intersects the xz-plane. What is your value of c? What is the equation?

    and then do the same thing for the yz and xy planes.

    I'm not sure at all what to do here. Thanks

    1 個解答Mathematics1 十年前
  • Can someone show me how to do this function problem?

    Suppose f(xy)=xy−6. Compute the following values:

    f(x+2yx−2y)=?

    f(xy4x2y3) =?

    I'm not sure where to start?

    1 個解答Mathematics1 十年前
  • Line of intersection between two planes?

    Hi, can you help with this?

    The planes 3x−5y+5z=−41 and 5x+3y+2z=−9 aren't parallel, they must intersect with line. What is the vector parametric equation for this line?

    I keep getting <t, 36/5 - 19t/5, -78/5 + 16t/5> but thats wrong...

    1 個解答Physics1 十年前
  • Line of intersection between two planes?

    Hi, can you help with this?

    The planes 3x−5y+5z=−41 and 5x+3y+2z=−9 aren't parallel, they must intersect with line. What is the vector parametric equation for this line?

    1 個解答Mathematics1 十年前