Math discussion/help

[jebckr]

I'll post some of the functions we're doing tomorrow. =)

 

[isosceles]

Anyhow, are you able to help with calculus as I'm thinking I'll have some trouble with it in a few weeks.

I'll do what I can. I'm starting to like calculus more these days .

Right now, in trig, I just finished doing functions. Those are a bitch, it's like they give you a function:

f(x) = x^2

Show me the proof of why that above function is Even.

I'll post the answer later when I have my trig notes.

There are a few steps involved in doing this problem, show them.

Btw, I'm a junior, and I am in Functions/Statistics & Trigonometry.

By definition, an even function satisfies: f(x) = f(-x). Therefore, we can put this: x^2 = (-x)^2. Is this true? Yep, that works (a little abbreviated, I know ). Go ahead and post your complete proof when you find it.

I'm glad to see some interest .

 

[Shredderbeam]

Well I meant without graphing the equation, there is a way to solve it algebraically.

Ah, well, my memory of 11th grade Pre-Calculus doesn't go back that far.

 

[enjoi888]

shredderbeam, for my problem u solved it for me... i got 1 prob with ur answer. my teacher always says check ur answer

yes u started it right the 2y was the denominator.

if u go to the orginal prob and plug in the 0.3 to the y and solve it out it doesnt wor...explain that

 

[Shredderbeam]

It was actually isosceles who solved it for you.

However, I took his solution of .3, plugged it in, and it worked out fine.

 

[jebckr]

We have functions of this sort coming up (4 chapters away). I'm assuming what I learn between now and then will prepare me, but as of now that sort of thing is more than I can handle.

 

[Tr1gg4]

lo lwe started calculus III today ._.,
when u use velocity speed time fuck... its bare dull

I always hated trig functions (sin cos tan)

 

[Shredderbeam]

We have functions of this sort coming up (4 chapters away). I'm assuming what I learn between now and then will prepare me, but as of now that sort of thing is more than I can handle.

Your link fails.

lo lwe started calculus III today ._.,
when u use velocity speed time fuck... its bare dull

I always hated trig functions (sin cos tan)

I love that stuff. :3

 

[enjoi888]

It was actually isosceles who solved it for you.

However, I took his solution of .3, plugged it in, and it worked out fine.

yea my bad

ur right it was isosceles and yea .3 works thx guys

 

[enjoi888]

another one

(3x^2)+5x+2=0

factor for quad function(need two answers) make both equal to 0 then solve

the first term is 3x squared

i should b able to do this but i am horrible at factoring, any1 got good tips for factoring

 

[Shredderbeam]

another one

(3x^2)+5x+2=0

factor for quad function(need two answers) make both equal to 0 then solve

the first term is 3x squared

i should b able to do this but i am horrible at factoring, any1 got good tips for factoring

(3x^2) + 5x + 2 = 0

(3x^2) + 5x = -2

x (3x + 5) = -2

Set both equal to zero:

x = 0

And:

3x + 5 = 0

3x = -5

x = -5/3

The two holes in the graph are x = 0, and x = -5/3.

And don't double post. >.<

 

[enjoi888]

sorry for double post

first of all my teacher is making me solve it by factoring

also 0 and negative5/3 plugged into initial equation doesn't work out

 

[isosceles]

(3x^2) + 5x + 2 = 0

(3x^2) + 5x = -2

x (3x + 5) = -2

Set both equal to zero:

x = 0

And:

3x + 5 = 0

3x = -5

x = -5/3

The two holes in the graph are x = 0, and x = -5/3.

And don't double post. >.<

You forgot the -2 you put on the right side of the equation. I would try factoring a little differently.


3x^2 + 5x + 2 = 0

Factor the whole thing. This takes a bit of practice and intuition. You have to think backwards sort of. You will start to see some patterns:
(3x + 2)(x + 1) = 0

Now look, If (3x +2) OR (x + 1) is equal to 0, the WHOLE thing will be equal to 0.

(x + 1) = 0 when x = -1.

(3x + 2) = 0 when x = -2/3.

Now plug the numbers back in and see if they work to check it.

Therefore, the graph of this function would intersect the x axis at (-1, 0) and (-2/3, 0).

Please, if you don't understand any of the steps or if you want me to explain the factoring I did a little more, tell me. There is no use for me to explain this if I'm not helping you understand it. If you do not understand this math, it will come back and bite you later when you go into more complex problems.

I sometimes skip steps simply because I have done quite a few problems. When you are learning something new, this is not a good idea. If you want me to go into more depth, tell me. I'm trying to help people get a better understanding of math .

 

[Shredderbeam]

Oh, wow, I'm sorry, I did it wrong.

(3x^2) + 5x + 2 = 0

Factored:

(3x + 2)(x + 1) = 0.

3x + 2 = 0

3x = -2

x = -2/3

And:

x + 1 = 0

x = -1

Well, if you factor it, you get -2/3 and -1, but you could always use the Quadratic Equation. In fact, if you have a graphing calculator, you can write a program that will work the equation for you.

 

[isosceles]

Oh, wow, I'm sorry, I did it wrong.

(3x^2) + 5x + 2 = 0

Well, if you factor it, you get -2/3 and -1, but you could always use the Quadratic Equation. In fact, if you have a graphing calculator, you can write a program that will work the equation for you.

Yeah, when in doubt, graph it. That can help give you a much clearer picture of what is going on. And yes, the quadratic equation is massively useful, especially when your equation is not easy to factor. I assume that enjoi888's class has not gotten there yet, however.

If you have a TI (Texas Instruments) graphing calculator, you can access a built in equation solver by hitting the "Math" button and selecting the "Solver" at the bottom of the list. Once again though, do not use this while you are learning to solve such equations or you will not grasp the concepts involved.

And yeah, you can write all sorts of cool programs on graphing calculators. I've written some to do such things as factoring numbers, listing rows of Pascal's Triangle, and all sorts of useful stuff. The possibilities are endless!

We have functions of this sort coming up (4 chapters away). I'm assuming what I learn between now and then will prepare me, but as of now that sort of thing is more than I can handle.

That forum does have quite a bit of interesting stuff on it. What sort of problems did you mean exactly? If you have any physics questions, I would be willing to give them a shot. I am taking physics also.

 

[jebckr]

My stupid link changed, it was a picture of a f(x) g(x) combined function. It had some negative tangents and a few imaginary numbers thrown in. Beyon me as of now. I'll draw one out on paint or something at school tomorrow.

 

[Jeffreycat]

Google the question and the problem. It might come up with an answer. As for ME doing math... I absolutely SUCK at it...!

 

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[I montage I]

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[I montage I]

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