redrims

Fellow protege owners, I really, really, need help. I know it probably looks kinda of silly putting my math homework on the forum, but no one on my floors knows this. Its amazing because the ppl that I've asked are in higher math than me like 140 and 220. And the math websites are confusing.

Anywho, here's the problem: (For pie, I just used 3.14...../I hope y'all know what it means and not to actually use 3.14, but the sign pie)

Suppose tant=4/5 and cost<0. Find each of the following:

a. cos(-t) b. sin(-t) c. cot(t+3.14.....)

d. sec(t+6[pie])


I really hope this makes sense and thanks.

ZoomZoomH

that's not calculus! that's trig!

redrims

Whoa, thanks for the help Hank.

It's still for my calculus class, but I know it's trig functions.

zchild92

redrims. Are those Trig Identities? It seems pretty simple, just plug and chug...though you'd need to know what cos is. Which Calc is this for? It might help us to know what section your working on.

redrims

Its for Math115 which is actually pre-cal.

I was also thinking plugging it in, but I don't think it is that simple. He wouldn't have given it to us if it was that simple.

gcs118

The only way I think the cos can be less than 0 is if the legs are -4 and -5, and the hypotenuse is radical 41. From there you can just plug and chug...I don't want to do too much work. If this is wrong sorry, just my thoughts!

redrims

Thanks. That makes more sense because now I realize that -4/-5=4/5 and that it will be in the 3rd Quadrant. Now I stiil have to find the rest.

Makaveli

okay so cosine is always smaller then 0 of t???
hmmm maybe I'm not reading something right....



This should be exactly the same as cos(t) since cosine is an "inverse" function (is that the word?)
anyways, there's a property that says that cos(t)=cos(-t)
for part c), adding a pie to 't' will only move it over and it will basically have the same value as long as you always add multiples of pie. Therefore, cot(t+pie) should be the inverse of tan(t+pie) which is again 4/5. Inverse of that is 5/4

Let us know the answers later.


Best thing is to draw them all and see what they look like. You will realize that adding multiples of 2(pie) or just (pie) for tangent functions simply moves you along the x-axis, but the value is still the same.
Good luck

ZoomZoomH

i would help you shem, but it's been SO LONG since i've messed with trig that I would need a quick refresher course before I'm of any use

go bug your TA!!!!!!! lol!

Makaveli

Plus it's hard doing math over the forum hahaha

redrims

yeah it is.
Your explanations were good and hepled. Thanks a lot. I turned my paper in and I hope I got them right.

I'll post the answers when get them. Since I don't officially have the answers yet, anyone can still try to figure them out.

This was a lot better than going to a math website.

Makaveli

Glad that I'm a geek and could help.

hihoslva

Hope you didn't have to spell pi on your paper, cuz it's not spelled pie!

Good luck, man - it's been 10 years since I touched any of this stuff. I was an excellent calc student, but it's all smoky (hehe) and faded now.

~HH

redrims

Yeah, I realized that after looking over my notes.

Makaveli

Yeah, why did I write pie too? Redrims, you're a bad influence


So were the answers right???

The whole forum is waiting on the answers