NationStates Jolt Archive

I've got a math exam on Thursday, the trigonometry problems will include the sin(x+y) and sinx+siny equations. I am assumed to know only the sine of 30 and 45 degree angles.

Ask me any questions you want for as long as they fit the above criteria.

Give the exact value of sin 15 (degrees).

What are the polar cooridinates of (12, 5) and (3, -10)?

Sin15=3^0.5/6

As for the other one... I don't really know what a polar coordinate is.

http://www4.ncsu.edu/~jack/trigquiz.pdf

What's trigonometry? :confused:

(13, ~22.6*)

(~10.44, ~-73.3*)

=pp



what is the x-coordinate of the line of length 5, 45* above the positive x-axis?

I always had 90+% in highschool math... until I hit trig. That year I had a bad teacher, and it was never well explained. :(

Deep Kimchi: a-a-d-c-d-e-d-c, unless I made a mistake somewhere. Wish my exams were this easy.

Quantum DiscoDiscord: 5/sqrt(2)=2.5*sqrt(2)

Gargantua City State: Same here. All exams 90+, then we started trigonometry this year and I'm down to 47 for the first exam.

I love math, just wish I could get back into it

Deep Kimchi: a-a-d-c-d-e-d-c, unless I made a mistake somewhere. Wish my exams were this easy.

Quantum DiscoDiscord: 5/sqrt(2)=2.5*sqrt(2)

Gargantua City State: Same here. All exams 90+, then we started trigonometry this year and I'm down to 47 for the first exam.

Haven't checked your work yet, but I have a question. What errors are you making to get a 47?

My daughter has a similar problem with changing math topics - it's purely psychological and causes her to make what I call "sillys". I have to coach her through it so she doesn't get as wound up.

Try this one
http://members.tripod.com/chuwm2/test/ch10.htm

What's trigonometry? :confused:

It's supposed to be "a system of measurement with triangles", but I like to call it "the stuff with the sines and crap".

It's a bunch of somewhat bulky formulas all based on this (http://img325.imageshack.us/my.php?image=trigo9al.jpg). Oh, and, cota is 1/tana.

Haven't checked your work yet, but I have a question. What errors are you making to get a 47?

My daughter has a similar problem with changing math topics - it's purely psychological and causes her to make what I call "sillys". I have to coach her through it so she doesn't get as wound up.

I wouldn't really call them "errors", it's more like my brain just shuts down for the first 30 minutes of the exam. About 6 of the questions were the circle-tangent line stuff which I had no idea how to do at the time. That is, not that I didn't know how to solve them, it's just that for some reason I couldn't think of it during the exam. Maybe I wouldn't have any problems if I didn't get so worked up about it, but that's easier said than done.

It does look like your making some simple mistakes from going too fast. Trig is different from other math classes in that you need to be more careful. Try number 5 again on the math test that Deep Kimchi gave you.

It does look like your making some simple mistakes from going too fast. Trig is different from other math classes in that you need to be more careful. Try number 5 again on the math test that Deep Kimchi gave you.

Looks like I took the sine instead. Should be e.

Looks like I took the sine instead. Should be e.

Yup. See what I mean. The key to Trig is to take your time and make sure you're looking for the right answer the right way. In other applications this was obvious, but in Trig for some reason people are constantly asked for A and give B. When you take this test. Look at the question. If you can't think of how to solve for what they're asking for start solving for anything. (Sometimes this will remind you of how to do what they're asking). When you do attempt to solve the equation presented, look at your answer and examine whether you solved for the right trig function or not. You'd be surprised how well you'll do on a test if you check your answer against the question.

In Algebra, it took seconds to figure out if your answer made sense. Say goodbye to the good old days. Now you actually have to know what you're doing. So what's the good news? You appear to know what you're doing. So trust in that and examine the questions and your answers until you get the answer that makes sense. I'll bet you'll see scores that are commensurate with your scores from other math disciplines.

All you need to know is the sine of 30 and 45 degrees?... what about the sine of 60 degrees? Or the cosine and tangent of these three angles? Or the sines, cosines, or tangents of any angle that has one of these three as a reference angle (such as 135, 210, 300, etc.)? I had to know all of these (and how to express them in radians, too) for trig...

Jocabia: Almost exactly what I've been telling myself for a while now. Guess it's the "answer that makes sense" part I'm having trouble with, when you start getting things like 1/sqrt(x^2-1) sense is difficult to hold on to. To top it off, it's not multiple choice. Still, thanks for the reassurance.

Adjacent to Belarus: (sinx)^2+(cosx)^2=1, you can get 60 from there. The 'circle gives you the sin(a*pi+x) angles provided you know sinx, same thing for cosine. tanx=sinx/cosx. I'm not sure you even have to memorize sin45, as if (sinx)^2+(sinx)^2=1 then sinx has to be sqrt(2).

Jocabia: Almost exactly what I've been telling myself for a while now. Guess it's the "answer that makes sense" part I'm having trouble with, when you start getting things like 1/sqrt(x^2-1) sense is difficult to hold on to. To top it off, it's not multiple choice. Still, thanks for the reassurance.

Adjacent to Belarus: (sinx)^2+(cosx)^2=1, you can get 60 from there. The 'circle gives you the sin(a*pi+x) angles provided you know sinx, same thing for cosine. tanx=sinx/cosx. I'm not sure you even have to memorize sin45, as if (sinx)^2+(sinx)^2=1 then sinx has to be sqrt(2).

Don't wish for multiple choice. Multiple choice is meant to mess you up. Look at how they got you to pick d for question 5. It was the answer you got, but it was the wrong question. Write out all of your work and check and see if you actually solved for what the question was asking for. I promise you'll do well. I was a tutor for many years, mainly in Trig and Calc. I have turned many an F student into an A student simply by teaching them to be more careful and more confident.