Some math problems

[Locust]

solve(give all solutions)
Sin(2x)=-2cos(x)
cos(3x)-root3/2

I really need help with these problems, as I have a test over them tomorrow. Could someone please tell me a solution?

 

[Ikerous]

Sin(2x)=-2cos(x)

x=pi/2,3pi/2
Wait a minute.. lol.. thats prolly wrong..
Bah >< Been so long ::Tries more::

cos(3x)-root3/2

Not entirely sure what you mean by -root3/2

 

[Hectic Glenn]

Well Ikky, your the maths pro here, no one has the passion like you do, so be our guest

 

[Ikerous]

Yea, i'm pretty sure the first one is x=pi/2,3pi/2

 

[Tr0n]

E=mc2?

 

[AntiAnto]

What do you mean by cos(3x)-root3/2

 

[Feath]

First one:

sin(2x) = -2cos(x)
2sin(x)cox(x) = -2cos(x) (Because of the identity sin(2A) = 2sinAcosA
Therefore sin(x) = -1

And I can't remember what that is, but you can look it up yourself

Edit:x = (3pi)/2

 

[Ikerous]

First one:

sin(2x) = -2cos(x)
2sin(x)cox(x) = -2cos(x) (Because of the identity sin(2A) = 2sinAcosA
Therefore sin(x) = -1

And I can't remember what that is, but you can look it up yourself

the sin(x) = -1 at 3pi/2
But when you divide both sides by cos(x)
You lose one of the points
So you also have to count when cos(x)=0
Which is pi/2 and 3pi/2

 

[Teh_Poet]

E=mc2?

That's actually a really intresting equation. I studied it back in the day.

 

[Feath]

the sin(x) = -1 at 3pi/2
But when you divide both sides by cos(x)
You lose one of the points
So you also have to count when cos(x)=0
Which is pi/2 and 3pi/2

Ahh, I get you. You mean

sin(2x) = -2 cos(x)
2sin(x)cos(x) = 0
0 = 0.

I understand.

 

[Locust]

Ah, I see now. thanks guys, you just enlightened my thought.

 

[Murray_H]

Explain integration to me as simply as possible!

You will recieve battenburg

 

[Feath]

Explain integration to me as simply as possible!

You will recieve battenburg

Opposite of differentiation. Kinda.

 

[Murray_H]

Opposite of differentiation. Kinda.

Explain differentiation to me as simply as possible!

You will recieve battenburg

 

[Feath]

http://en.wikipedia.org/wiki/Derivative

 

[Ikerous]

Explain differentiation to me as simply as possible!

You will recieve battenburg

The instentanious rate of change of a function at any given point
Its like the average rate of change (rise over run)
When the run is 0

 

[Murray_H]

http://en.wikipedia.org/wiki/Derivative

Cheers, I always forget about wikipedia

I wish I had taken A-Level maths, it would have been bloody useful for the course I'm taking

 

[Sprafa]

I can't multiply 1 for 1

REally, my math brain part is dead.

 

[xLostx]

1 + 1 is 3

 

[AntiAnto]

1 + 1 is 3

Well, he's asking about multiplications. So 1 × 1 = 4.3333, in this case.

 

[Kebean PFC]

Go to purplemath.com. It is not my site, and i am in no way affiliated with it, but it had helped me out a lot.

 

[evil^milk]

E=mc2?

i really dont want to sound like a bitch, but refrain from posting unless you have something useful to post

 

[Ikerous]

i really dont want to sound like a bitch, but refrain from posting unless you have something useful to post

Lol, i can just imagine off-topic if everyone followed that ideology
The place would be completely barren

 

[evil^milk]

sure, but... when you know it shouldn't have been posted...