Science & Mathematics - 13 October 2007

Hi, please tell me what I'm doing wrong because I can't figure it out! I'm supposed to solve this trigonometric equation on [0, 2pi).

It is:

6cos²x + 5cosx + 1 = 0

I figured that I'd solve it with the quadratic, simple enough.

-5 +/- √(25 - (4)(6)(1)
------ --------- --------- --
12

=

-5 + 1
---------
12

and

-5-1
-------
12

Giving me -1/3 and -1/2. I then discarded the -1/3 (which I apparently shouldn't have), and got values of 7pi/6 and 11pi/6 for the -1/2.

What I'm thinking is that I should have used a calculator and done the arccos for both (-1/3) and (-1/2). Would that be the right thing to do?

Thanks so much for any help! I'll pick a best answer TODAY!!!!!

2007-10-13 05:29:12 · 5 answers · asked by Anonymous in Mathematics

Do you like sausages?

2007-10-13 05:25:46 · 4 answers · asked by wormyfeatures 2 in Other - Alternative

for example the industrial revolution and the internet

2007-10-13 05:24:16 · 9 answers · asked by hello 3 in Engineering

advanced civilizations

2007-10-13 05:23:49 · 24 answers · asked by Anonymous in Astronomy & Space

if you answer all of these in order. u will get a surprize.
i need a science teacher or a science professor.

ok number 1

the earliest fossils are of
a) dinosaurs B) plants C) one-celled organisms D) marine animals

which of the following is also known as a spreading center.

A) transform boundary B) divergent boundary C) convergent
boundary D) convection boundary

please be honest with your answers and if you dont know dont answer this question.~!
i mean it! first correct person to answer all of them correctly wins something big!!!

2007-10-13 05:23:19 · 3 answers · asked by Davyy♫ 5 in Earth Sciences & Geology

Find an equation for the plane that contains the line with parametric equations x = −1+3t, y = 5+2t,
z = 2 − t and is parallel to the plane 2x − 4y + 2z = 9.

2007-10-13 05:21:47 · 3 answers · asked by Eric W 2 in Mathematics

2007-10-13 05:19:59 · 5 answers · asked by Anonymous in Earth Sciences & Geology

2007-10-13 05:18:58 · 2 answers · asked by Anonymous in Earth Sciences & Geology

Help me I can not do word problems at all
winter wheat- while finding the amount of seed needed to plant his three square wheat fields, Hank observed that the side of one field was 1 kilometer longer than the side of the smallest field and that the side of the largest field was 3 kilometers longer than the side of the smallest field.. If the total area of the three fields is 38 square kilometers, then what is the area of each field

2007-10-13 05:10:55 · 4 answers · asked by mormar 1 in Mathematics

Plz

2007-10-13 05:05:28 · 10 answers · asked by Christina B 2 in Geography

In Italy a little mountain broke down yesterday because too hot weather same he spoke in his film!!!

2007-10-13 05:03:09 · 6 answers · asked by stefano n 7 in Weather

PROBLEM: how do charged objects interact with each other?

how did identical charged objects interact with each other? For example, how did one charged comb interact with the second charged comb?
PLEASE HELP I WOULD SO APPRACTIATE IT
like :
plastic comb (charged object in hand)
plastic comb(Charged object on watchglass)

How did differently charged objects interact with one another?
Conclusion:
how do neutral objects interact with charged objects?

how do charged objects interact with other charged objects?

How is this information useful in society?

2007-10-13 05:02:56 · 2 answers · asked by Anonymous in Chemistry

I need help with how to do with problem. If someone can show me the steps. I really don't get this.

An object is launched at an angle of 20 degrees with a speed of 30 m/s. It hits 4.0m up the face of a wall. How far away is the wall? (Note: Use Quadratic formula to find time.)

2007-10-13 04:59:44 · 2 answers · asked by neverisenough 1 in Physics

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the colors are like looking into a mirror beside it, but both rainbows are parallel

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INFORMATION IS CHANGE FROM ONE FORM TO ANOTHER FORM BUT IT IS NOT DISTROIED CAN WE APPLY ENERGY CONVERSATION THEOREM TO IT.

2007-10-13 04:53:05 · 3 answers · asked by Anonymous in Physics

2007-10-13 04:49:43 · 2 answers · asked by anthony m 1 in Engineering

who would i talk to in this small town in georgia about getting some tornado sirens.we were lucky last time.just trees down and structure damage.no deaths thank God!they seem to be using the monies for something else.

2007-10-13 04:47:09 · 6 answers · asked by honeypot0214 4 in Weather

so this Mosquito alarm thing is the alarm they have installed around malls and stuff to stop teens from loitering and all. but not people have been getting it on their phones and suff, so it has like just become like a big deal around where i live, so i was looking it up and i played an mp3 of it and my mom could hear it! like shes in her 40s.. was it not the real thing or does she just have really good ears..? haha. i dunno! but if you guys know of a link to the real thing then i would love to have it. thanks!

2007-10-13 04:44:46 · 1 answers · asked by Anonymous in Other - Science

natural gas has keep it buring for over 500 years and the gas is all free.

2007-10-13 04:42:33 · 4 answers · asked by ronstevens44 1 in Earth Sciences & Geology

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Show that the tangent to any point (a,a^3) on the curve y=x^3 meets the curve again at a point where the slope is four times the slope at (a,a^3)

2007-10-13 04:36:34 · 4 answers · asked by NEBA 1 in Mathematics

The Sell-Rite Corporation sells men's ties.The ties are priced at $26 each and they have been selling an average of111 per week.A consultant has determined that for each dollar the company reduces the price of ties, an additional13 ties would be sold.1.Write an expression in terms of x for the following:a.he cost of ties afster its price is reduced by $x.b.the # of ties sold per week after the price id reduced by $x. c.he sales revenue per week after reducing the price by $x.2.What price reduction, to the nearest cent, will maximize the sales revenue on ties?3.At this price reduction, find the new selling price and the average number of ties Sell-Rite can expect to sell per week.4.Sell-Rite spends$11.50to purchase each tie. They will consider only price changes that result in net profit (they will not sell ties for less than it costs to make them).Under these conditions,find the domain and range of the revenue function.How would this change if Sell-Rite could produce the ties for $9.75

2007-10-13 04:33:30 · 2 answers · asked by Thanh Thao 1 in Mathematics

2007-10-13 04:29:31 · 5 answers · asked by Anonymous in Earth Sciences & Geology

2007-10-13 04:21:17 · 1 answers · asked by Anonymous in Earth Sciences & Geology

Hi all! i'm willing to know about the nim to ttl circuit..here i have its website address:

http://lyoinfo.in2p3.fr/cms/cmsecal/TTL_NIM%20user%20manual_v10.pdf

I'm doing the part of 2.2.Since the codes of the components aren't very clear, so i cant find the exactly components of the circuit..and i have to built the circuit in Multisim after i found the exactly components to test it.so the components that i found must be matched with the code of components in multisim,or else it cant be use.

1) Anybody can tell me what exactly are they for those components?
2) Now i roughly know the second component is a ttl(7486N),and the third component(from the left) is octal 3-state buffer(DM74LS244),and the first one is an op-amp..Is it correct?
3) How large of capacitance for the polar-capacitor for this circuit roughly?
4) Where can i get the input for NIM?
5) Anybody can tell me what is NIM signals and TTL signals?

THANK YOU^^

2007-10-13 04:19:18 · 2 answers · asked by Anonymous in Engineering

I want to know if this symbol * is used in the unit of measure of pound?
Thank You

2007-10-13 04:18:42 · 8 answers · asked by joy752002 1 in Mathematics

h = –16t^2 + 90t + 10

How long will it take the object to hit the ground? Round your answer to the nearest thousandth.

2007-10-13 04:16:41 · 3 answers · asked by Joe T 1 in Mathematics

(Not the from another country alien the not-from-earth aliens)
Oh and heres another question : Im really really bored any suggestions on mmorpg's or sumtin?

2007-10-13 04:06:49 · 25 answers · asked by Anonymous in Astronomy & Space