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When is it required to use the quadratic formula?

abel muroi

Junior Member
Joined
Jan 13, 2015
Messages
210
I don't mean ax[SUP]2[/SUP]+ bx + c

I mean the other formula with the square root. Btw i don't know how to type the formula here, but I assume you know which formula I'm talking about
 

Subhotosh Khan

Super Moderator
Staff member
Joined
Jun 18, 2007
Messages
18,089
I don't mean ax[SUP]2[/SUP]+ bx + c

I mean the other formula with the square root. Btw i don't know how to type the formula here, but I assume you know which formula I'm talking about
Please post a problem - so that we discuss the specifics.

We cannot discuss generalities here - you need to ask that in your classroom.
 

abel muroi

Junior Member
Joined
Jan 13, 2015
Messages
210
Please post a problem - so that we discuss the specifics.

We cannot discuss generalities here - you need to ask that in your classroom.
OK so i was given this problem..

p(x) = x[SUP]4[/SUP] + 4x[SUP]2[/SUP]

can i use the quadratic formula for this problem? even though it doesn't have a third term?
 
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Jomo

Elite Member
Joined
Dec 30, 2014
Messages
2,767
OK so i was given this problem..

p(x) = x[SUP]3[/SUP] - 2x[SUP]2[/SUP] + 2x

can i use the quadratic formula for this problem?
You are not asking a question. Are you trying to find p(5). If so, then you do not need to use the quadratic equation. If you want to find the y-intercept then you let x=0 and do not use the quadratic formula. If you want to know what happens to p(x) when x is very large you do not use the quadratic formula.
In fact you never have to use the quadratic formula.

Also most people would only think about using the quadratic formula when the function is quadratic not cubic.

You seem to have the idea that given a particular function that there is just one thing to do to it so there is no need to ask a question because the question is obvious. Move away from that thinking.

Good luck.
 

Subhotosh Khan

Super Moderator
Staff member
Joined
Jun 18, 2007
Messages
18,089
OK so i was given this problem..

p(x) = x[SUP]4[/SUP] + 4x[SUP]2[/SUP]

can i use the quadratic formula for this problem? even though it doesn't have a third term?
You are not telling us what did you need to do!! That's what will determine whether you need to use quadratic for this problem - or not. Please be complete!!
 

Jomo

Elite Member
Joined
Dec 30, 2014
Messages
2,767
OK so i was given this problem..

p(x) = x[SUP]4[/SUP] + 4x[SUP]2[/SUP]

can i use the quadratic formula for this problem? even though it doesn't have a third term?
Abel, all you did was change the function! You still are not asking a question. For the record p(1) = 5 and I did not use the quadratic formula.
 

abel muroi

Junior Member
Joined
Jan 13, 2015
Messages
210
Abel, all you did was change the function! You still are not asking a question. For the record p(1) = 5 and I did not use the quadratic formula.
sorry, the problem is asking me to find the complex roots of the function..

but my question is... how can i factor out this function?
 

catendra

New member
Joined
Mar 12, 2015
Messages
1
Quadratic formula

I think you mean "the quadratic formula". You can use the quadratic formula for any quadratic equation to find the solutions. The solutions are the x-coordinates of the intersection of the curve with the x-axis. When the curve does not cross the x-axis you get a minus sign inside the square root and you cannot take a minus sign of a square.
 
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