Let's make a homework help thread!

Start with the angles. Once you have all the angles filled in, you can start applying the law of sines to get the distances. The angles determine the shape of the object and the ratios of the sides lengths, after that side m just gets you the scale. If you still have the issue tomorrow after noon, I'll try and add some stuff to help you along.

edited 19th Nov '09 1:13:39 AM by Deboss

The issue in question is that there are not enough angle measurements (or, rather, not enough of the right ones) in order to determine the shape up to similarity (before we factor in the lengths). The angles we know are enough to determine triangle QRS, but they only give us one angle of PQS, which isn't enough to determine the angles of that triangle. Getting any one angle more (other than angle RQS or angle PSQ—or of the angles that are obviously 180 degrees, of course) would actually give us enough information. So would some of the side lengths. As it stands, though, these for pieces of information are not enough to determine a unique quadrilateral.

I looked at in depth, and I'm going to have to agree. I only pulled another two angles out of it PSQ, and SQR. Unfortunately I'd need at least one more piece of data to finish this. I've done part of it, so if you want partial credit, I'll upload a shot of the scratch. Judging by the way it's asking for angle R when it gives us SRQ and the weirdness of the question I'm guessing they rearranged some of it and left a bit out. One more piece of data would make this solvable, any distance or an angle we don't have and that would be it.

Notes◊

edited 19th Nov '09 5:05:57 AM by Deboss

Are you supposed to presume that the angles at T are all right angles? and what's angle R? R and what other two points? Some piece of information is missing.

Yeah, that's what we noticed. Since it's asking for the upper angle T it's not right angles. We need another bit of data to pin the object down.

When I went into class today, I found out that she had indeed forgotten to give us an angle. Once I got it, it was so much easier. Thanks for trying to help, though.

So it's the teacher's fault. HAHA!

Which is actually odd, because she's a pretty good teacher. Doesn't typically make mistakes like that.

I just like poking fun at teacher mistakes.

Ah. Yeah, I can understand that. I do that too, when it's a bad teacher.

I do it to my English teacher.

On another note, i have an essay due monday. Can anyone think of common themes between Psycho, The Birds, and Vertigo?

Sorry, I haven't seen Psycho recently enough to talk about it and I've only seen the end of the Birds. And it was in Spanish.

ah, oh well.

She Failed a Spot Check, it happens. I haven't found a teacher yet who won't forget something or another. The principle was sound, yes?

Moving fast are we? The only thing I can think of between the three is that they're horror. You might want to look into why they're horror.

edited 19th Nov '09 2:27:01 PM by Deboss

If by that you mean I could figure it all out quite nicely with Law of Sines and Cosines once I had the angle, then yes.

Yay, we were helpful.

@ el the daze: Look at Wikipedia's article on Hitchcock for some ideas of where to start.

I'm now writing my essay on how physics apply to electric and acoustic guitars.

Yeah, yeah, soundwaves and vibrations and all that garbage. can anyone put it in layman's terms for me? I'm feeling kinda stupid right now.

@ El The Daze: for some odd reason, Hitchcock was a sucker for Blonds.

edited 20th Nov '09 11:46:55 PM by Schitzo

1. Pluck the string.
2. String vibrates.
   • Depending on which fret, the length of the string that can vibrate increases or decreases.
3. String causes air to vibrate.
   • Longer string (higher fret) = lower frequency = lower note, shorter string (lower fret) = higher frequency = higher note
4. I know jack about amps
5. Ear stuff

yeah tired whatever

edited 20th Nov '09 11:48:17 PM by Tzetze

Speaking of Sine and Cosine...

"Find the exact value of each expression. Do not use a calculator."

"csc 37° sec 53° - tan 53° cot 37°"

And "Express the exact value of each function as a single fraction. Do not use a calculator."

"If f(Θ)= 2 cos Θ - cos 2Θ, find f(π/6)."

This is the one time the book failed to explain anything it was asking... It doesn't even tell you how to figure out what the sin/cos/tan/etc. of a degree or radian is without using a calculator...

edited 21st Nov '09 8:25:28 AM by Miijhal

For the first one, I'd start by just trying to simplify it...

Secant was 1/cosine, right? Then cosecant is 1/sine, I'm sine/cosine, and cotangent is cosine/sine.

edited 21st Nov '09 1:24:01 PM by Tangent128

Well, tan x * cot x = 1, but I don't know how that works with different values.

And hell if I remember the half-angle identities. Damn those things.

[1]

edited 21st Nov '09 1:25:13 PM by Tzetze

Alright, let's get you started with the unit circle. The x-coordinate correspond to the cos and the y-coordinate corresponds to the sin. If you have to evaluate any trigonometric function at one of the angles on the circle, write that function in terms of sin and cos, then plug in the values you get from the circle.

With the unit circle, the second question should be easy. In the first question, on the other hand, none of the angles correspond to those on the unit circle, so we'll have to perform some simplifications first.

First, go ahead and write all of the functions in terms of sin and cos, then write the entire expression one fraction. One thing we can notice is that 37=90-53, so we can write all of the functions that have 37 degrees in terms of (90-53) degrees. Since we know the double angle formulas for sin and cos, we can use those to get rid of all terms with 37 degrees. Remember to use the unit circle to evaluate sin(90) and cos(90)! At that point, your entire expression will be in terms of sin(53) and cos(53). Using some basic trig identities, (such as the Pythagorean identities), you should be able to reduce the expression into something that does not depend on sin(53) or cos (53) (since we don't know how to evaluate those, after all).

edited 21st Nov '09 4:19:19 PM by Ironeye

^That looks like it, the only other thing I could add would be to remember SOH CAH TOA if you want to take it to x,y,r. But I don't think you'd need to go that far.

Thank You, Tzetze. now i know how to structure my paragraphs.