Quadratic equation with no real solution.

CIV · 2015-03-13 10:56:12

This is the problem:

Solved. No real solution.

My question is, how do you calculate values with the imaginary number? I know how to verify that I solved it correctly but how do I generate values with the imaginary number? What do I do with the "i"?

Thanks.

zetafunc · 2015-03-13 11:11:56

For the purposes of your calculations, you most likely only need to know that i² = -1: that should suffice.

Do you know what a complex number is?

CIV · 2015-03-14 06:37:47

Sorry for the late reply. A+Bi? I'm aware that "i squared" equals -1 but the i isn't squared.

zetafunc · 2015-03-14 07:18:13

Yes, all complex numbers can be represented in the form a + bi, where a, b are real numbers. With them, we can define addition and multiplication as follows:

Some examples:

We also have some other properties, such as conjugation:

There exist even more interesting algebraic structures, such as the quaternions (which are not commutative) and the octonions (which are not associative!).

CIV · 2015-03-14 13:24:42

That I know. But how do I derive values from what I posted originally? when I put the equation into the graphing calculator it draws a graph. I want to know how it came up with the values despite having a complex solution.

CIV · 2015-03-14 14:38:40

Ahhhh you know what, I feel so stupid. My brain is cooked. Well it's not now because i actually got some good sleep after doing so much math homework. I figured out what it is that what confusing me about all this while driving to work. Solving quadratic equations for solutions is only to see if the equation intercepts the x axis. If i get a complex solution this means there is no x intercepts and thats it. There is no solving it anymore. the solution is not used to draw the graph. I dont know why i thought this. Thanks for your help.

zetafunc · 2015-03-15 20:32:17

Not a problem. Sometimes the best way to become unstuck on a maths problem is to simply do something else.

Math Is Fun Forum

#1 2015-03-13 10:56:12

Quadratic equation with no real solution.

#2 2015-03-13 11:11:56

Re: Quadratic equation with no real solution.

#3 2015-03-14 06:37:47

Re: Quadratic equation with no real solution.

#4 2015-03-14 07:18:13

Re: Quadratic equation with no real solution.

#5 2015-03-14 13:24:42

Re: Quadratic equation with no real solution.

#6 2015-03-14 14:38:40

Re: Quadratic equation with no real solution.

#7 2015-03-15 20:32:17

Re: Quadratic equation with no real solution.

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