I wasn’t sure where to post because my question has to do more with algebra, but I’m on a problem in a book I’m working out of and this one little hiccup is stopping me from completing it. Formula for exponential smoothing forecast is: alphaYt + (1-alpha)Ft The time series goes to 13 and the problem wants to continue to expand the expression until it is written in terms of the past data values going back until period 8. I’m using alpha = 0.2 Starting with F13 = 0.2Y12 + 0.8F12 I know F12 = 0.2Y11 + 0.8F11 so I can take that and plug it back into F13 to get F13 = 0.2Y12 + 0.8(0.2Y11 + 0.8*F11) = 0.2Y12 + 0.16Y11 + 0.64F11 The answer in the book is 0.2Y12 + 0.16Y11 + 0.64Y11 + 0.64F11. I know my algebra is a little rusty but not sure where they pulled the 0.64Y11 from. This is the only thing holding me back from getting the answer submitted by Nevin Manimala Nevin Manimala /u/VwDKplay [link] [comments]
I am hopefully going to purchase a soft top convertible tomorrow morning. One of my concerns is prolonging the life of the top. One thing is I have indoor/outdoor cats. They love to climb my current car and leave prints all over the place. I know for a fact they will scratch the soft top up. I need a way to protect it from the cats without being too much of a hassle. One thing I considered is maybe is getting a good car cover and just keeping the top down when the cover is on it. This way if they stick their claws through the cover, it won’t get the soft top. I’d love any suggestions though. Since I’ll be daily driving this thing I’d rather it not be too big of a deal.
Disclaimer – I’m hopeless with numbers. I haven’t studied maths for over 20 years. Please forgive any unfamiliarity with terminology or descriptions.
So recently I was showing a friend some pictures of my cat, because why not.
Friend mentioned that Sleeping Cat was lining up nicely with the Golden Ratio, (which I’ve heard of via pop culture references but never really explored, due to the whole “being hopeless with numbers” thing).
I called bullshit, because the little “knowledge” I DO have relates to nautilus shells, unfolding plant stems etc. I’ve always thought of it as a spiral, lengthening out from a central point to a long curve. But it got me thinking…
Is the Golden Ratio / Fibonacci equation found only in living / once living organisms such as fossils, or does it naturally occur in inorganic examples too? (Geology or Geography, for example). I know that we can construct, sculpt or draw things which conform to the ratio, but are there examples which are due to physics rather than biology, and outside of human influence? Is the ratio a universal occurrence?
Thanks for any input which doesn’t mock my ignorance!