how do you sketch 2x^3 + 9x^2 + 12x + 1 (1 Viewer)

[M@ster P]

the title says it, i have no i dea how to sketch the function 2x^3 + 9x^2 + 12x + 1

 

[M@ster P]

the problem is i am year 11 and havent learnt calculus yet, the question relates to polynomials.

 

[Aerath]

the problem is i am year 11 and havent learnt calculus yet, the question relates to polynomials.

We've learnt Calculus. We're in Yr 11.

Using Factor R/S doesn't work either. =\

 

[M@ster P]

We've learnt Calculus. We're in Yr 11.

Using Factor R/S doesn't work either. =\

well i dnt learn calculus until term 3, but yeah the factors dont work as none of them make the equation equal to 0, meaning no x roots

P.s i looked at the answer and the graph never cuts through the x-axis, explaining the reason why there are no roots, it cuts the y intercept at 1 (make x = 0 ) and it has two turning points at (-2, -3) and (-1, -4). How did they obtain the turning points without using calculus?

 

[tommykins]

Do what JSIN has told you to.

The equation is too hard to find any x intercepts, although there is one at x = -0.1

 

[tommykins]

well i dnt learn calculus until term 3, but yeah the factors dont work as none of them make the equation equal to 0, meaning no x roots

P.s i looked at the answer and the graph never cuts through the x-axis, explaining the reason why there are no roots, it cuts the y intercept at 1 (make x = 0 ) and it has two turning points at (-2, -3) and (-1, -4). How did they obtain the turning points without using calculus?

You can't.

And it does cut the x axis, how can a cubic not cut the x axis but can cut the y-aixis?

 

[Aerath]

Well, I wouldn't know how to do it without calculus.

Edit: Tommykins just said you can't

 

[M@ster P]

this question relates to the topic i am learning now which halving the interval, well can you do this question based on this topic

 

[M@ster P]

lol

 

[M@ster P]

I cheat

But yea, I'm in uni, and 4 unit maths looks like childs play

wow then the maths ur doing must be incredibly difficult

 

[M@ster P]

no its just first year maths, we roll over complex numbers in a couple of weeks

Talk to some of the older engineering students, then you know what real maths is.

my course i want to get into is civil engineering so i will find out

 

[M@ster P]

i will

 

[Aerath]

Graphmatica.

Go download it.

RIGHT NOW.

+1

 

[tommykins]

this question relates to the topic i am learning now which halving the interval, well can you do this question based on this topic

ah if that's the case, sub x = 0, you get y = 1

sub x = -1, you get y < 0, thus a root exists between -1<x<0

use -0.5 as an estimate, sub it in the formula

x2 = x1 - f[x1]/f'[x1]

where x2 = new interval, x1 is -0.5

my course i want to get into is civil engineering so i will find out

Heh, my friends doing that and he's bitching about the amount of work he has to do with physics. He did 4unit so i guess the mathematical side of it isn't annoying him too much.

are you planning to do 4u?

 

[BIGTYMA]

edit thumbnail anit working.

 

[M@ster P]

ah if that's the case, sub x = 0, you get y = 1

sub x = -1, you get y < 0, thus a root exists between -1<x<0

use -0.5 as an estimate, sub it in the formula

x2 = x1 - f[x1]/f'[x1]

where x2 = new interval, x1 is -0.5



Heh, my friends doing that and he's bitching about the amount of work he has to do with physics. He did 4unit so i guess the mathematical side of it isn't annoying him too much.

are you planning to do 4u?

well too be honest with you no, i will only be doing 3 unit.

3 unit is enought to start, as civil engineering requires 3 unit as assumed knowledge, but yeah if u can do 4 unit it would be an advantage but if u don't no biggie. I will only be doing 3 unit because atm i dnt think i am capable of 4 unit, but sooner or later i will have to learn anyway as i will encounter it in civil engineering.

What course are you looking into? Perhaps civil engineering as well? your doing 4unit maths so you are at an advantage