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The Fishman

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jeels said:
can someone do the ratio test on (3^K)*(K^2) / (K!)
Click to expand...

Sure, one sec. Just had an exam on this stuff.

Unless I did something wrong, it should simplify to (3(k+1))/(k^2). Then apply the limit and you should get 0, which is less than 1 and therefore the series converges.
 
Nostalgia

Nostalgia

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The Fishman said:
Stupid question since most math placement tests aren't, but is this a multiple choice question? Also, I'm guessing you need to find what that exact angle is? This isn't a surefire way to go about doing the problem, but I would try drawing out the unit circle and draw a line with a slope of 3/4 to get an idea of where the point and estimate of the angle is. In correlation to that, you could try drawing a line with slope of 1 since you should know that arctan(1) is equal to pi/4. Since y = (3/4)x is under y = x, you know the angle is a little less than 45 degrees and multiplying it by 2 should still keep you in the first quadrant. So you know your angle should be between about 70 and 90 after multiplying by 2. I know this probably doesn't answer your question or help you at all, but I thought I'd give it a shot and maybe help you see the problem in a different way so you can solve it.

By the way, I believe arctan(3/4) = 36.87 degrees or something like that. So you should have something like cos(73.??). I would guesstimate it to be around .25.

Edit: Or you can try something like these: SOLUTION: Evaluate without a calculator: A) sin{ Arctan [(-5/13)]} B)cos{ Arcsin[(-3/4)]} C)Arccos[(-square root of 3/2)] D) tan { Arcsin[(-3/4)]}
I don't think they would make you simplify these types of problems on a placement exam, but I'm not too sure.
Click to expand...

Lol, yeah, it was stumping me for a while too. I ended up getting help from a friend who's taking calc. The idea is that you take the cos(2arctan(3/4)) expression and make arctan(3/4) = x so that you have cos2x. From there, you just plug in for one of the identities, making it cos^2x - sin^2x. Since opp/adj = 3/4, we know that it's a 3,4,5 triangle, and that the cos^2x = (4/5)^2 or 16/25. Similarly, sin^2x = (3/5)^2 or 9/25. So, you subtract and get 7/25 as the answer.

Really, I didn't need to put that, but I figured the idea might help someone else in the future.
 
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Roa

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i forgot how to clear demicals and fractions.. well not that I ever did.

2/3x *4/4 - 3/4x < - 3/4

I am utterly confused... Well no, I know how to do it, but I'm supposed to clear the fractions, which I have no idea what-so-ever how to do....
 
Hollow Bastion

Hollow Bastion

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Lord Marluxia said:
i forgot how to clear demicals and fractions.. well not that I ever did.

2/3x *4/4 - 3/4x < - 3/4

I am utterly confused... Well no, I know how to do it, but I'm supposed to clear the fractions, which I have no idea what-so-ever how to do....
Click to expand...

*decimals, I assume

And by clear the fractions, do you mean just remove the fraction so they're just integers? If so, find what they have in common.

All 4s and 3s, so multiply the whole thing by 12. That'll remove the 4s and 3s.

Becomes
8x * 1 - 9x < -9

And assuming you didn't leave off parenthesis or whatever, that becomes
8x - 9x < -9

And I'll let you take it from there.
 
T

The Fishman

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Nostalgia said:
Lol, yeah, it was stumping me for a while too. I ended up getting help from a friend who's taking calc. The idea is that you take the cos(2arctan(3/4)) expression and make arctan(3/4) = x so that you have cos2x. From there, you just plug in for one of the identities, making it cos^2x - sin^2x. Since opp/adj = 3/4, we know that it's a 3,4,5 triangle, and that the cos^2x = (4/5)^2 or 16/25. Similarly, sin^2x = (3/5)^2 or 9/25. So, you subtract and get 7/25 as the answer.

Really, I didn't need to put that, but I figured the idea might help someone else in the future.
Click to expand...

Don't know why I didn't think of that. It's a lot more "cleaner" and less guessing. Glad you got some help with it that worked.
 
ICECOOL113

ICECOOL113

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I'm not so sure if this is for help in math but since it is homework help I have a question.
OK well in my English class we are finishing up reading the novel The Color of Water in the newest version (the purple book if no one or someone knows). We are assigned to create at least 7 disscussion questions and we are not supposed to use the reader guide in the back of the book.
Can someone please at least tell me 3 disscussion questions I can use. THANK YOU!
 
Pelafina

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ICECOOL113 said:
Can someone please at least tell me 3 disscussion questions I can use. THANK YOU!
Click to expand...

I doubt anyone will come along that's read it, and I haven't either, but I'll try to give you some technique at least.

Symbolism is always an easy one. Think of something that could have been a symbol, and ask if it was, and how. Teachers love symbolism questions. If there were any loose ends at the end of the book, ask what could have happened with those based on what you knew. Ask about character traits too, what made a character make a decision that they did, or do something they did, or whatever.

You should be able to figure something out from there.


Also, I just realized that I'm bumping a month-and-a-half old post, but I already typed it, so I don't give a fuck. It's still good advice.
 
Coffee Lover

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I didn't take ANY Chemistry in High School and I'm about to start Chemistry 1 in a bit. Should I be concerned? I'm asking this because, even though I study constantly right now in Summer School, someone suggested I get a Chemistry book and look over it a bit. Also, there have been some classes I've took that don't teach the basics of things, things I learned in High School.
 
Et Cetera

Et Cetera

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Sitting in the library taking notes on this book, I can't check it out because I'm leaving this weekend and it'd be due before I get back XP
My question is: When I start writing my essay, how should I handle/cite a source that cites other sources?
Like, I'm taking notes from this book, and some of the stuff I'm pulling from it has yet more citations.
 
Omni Terra

Omni Terra

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Not sure if this is the right place but I figured it would be better than creating an unnecessary thread. So, I'm about to go back to school and I have signed up for the more advanced classes. Advanced Algebra 2/ Trig. and Chemistry. Is there anything I should maybe brush up on to make my life easier?
 
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