Using the Discriminant in a Quadratic Equation

[MrAstroKind]

This is great, I understood how to do this before this video but it's good revision!

[XopenwideX]

I use this to finish my homework and to finally understand it! (my teacher sucks)

[MrPimpdaddy8]

5/5 you made it easier on my head!

[bobmarley789456]

Great video this was really helpful

[dardi1111]

im 16 we use imaginary numbers could u pls answer this in a video

Re(z(2+1))=1 IM(1/2+i)=-3/5

[devpwner]

For example two, you could answer it by taking the negative off of -71 and put I infrount of the square root indicating you have imaginary numbers. from there you would simplify the number in the square root which would be +71 if possible.

[XxAngelShinn]

omg you helped me so much thanks!! im in kumon and this self studying/learning isn't working for me anymore and after you explaned it to me i really got why and how to use it, thanks so much!

[yeegf]

kumon is hopeless.

use youtube.

tell everyone you know in kumon.

[XxAngelShinn]

dude i agree with you 100% but my dad makes me go =/

[ragtimest]

awsome~!!!

[MetalSwitch95]

If the discriminant = 0

a) You have a perfect square trinomial

b) The x-axis is tangent to the vertex. In other words the vertex hits the x-axis.

[DarkWolfen]

No answer for a negative square root? What about i? A complex number?

[minkusbc]

Of course imaginary and complex numbers can be used. But at the high school level, these are usually not discussed until calculus. However, as curriculums change, I may redo this and add it in. Thanks for your interest.

[MrPimpdaddy8]

@minkusbc hey im in algebra 2(11th grade) and i have learned that i is a imaginary number bcuz the square root ends up negative...is that right?? thats what yall talking about?? is my teacher correct or shes stupid like i??

[7xStevenx7]

You know you're a really good teacher. You help out a lot.

[gamernaveen]

There is a concept called 'i' , for negative square roots , if am not wrong . Anyway great video.

[Supersmashbrojory]

i is the square root of negative 1. i is short for imaginary. If i is a zero of any function, so is negative i because the f(x) has to be a real number.

[Killaxcon]

Great step by step. thanks for the help.

[MathMikie]

for the example 2 they was an anwer 2 complex roots

[douluvmee]

how much i wish you were my math teacher....

[shoes202]

you never discussed the discrimant how to find it! Why use it in ur title if ur not even gonna talk bout it?

[minkusbc]

I show in the first step - it is the b^2 -4ac part of the quadratic formula. A quick look at the value of the descriminant will tell you how many answers your equation will have.

[Supersmashbrojory]

Or better yet, just look at the degree of the function. If you are using the quadratic formula, you are dealing with a quadratic function and a quadratic function has two x values in which f(x)=0. The degree of your function is how many zeroes the function has, the degree being largest exponent.

example: f(x)=x squared+x+1. the highest degree is two therefore, you will have two zeroes.

[minkusbc]

You still need the discriminant to tell you how many of those zeroes are real numbers and how many are imaginary numbers. Most Secondary math curriculums do not discuss imaginary numbers until calculus or advanced placement.

[bobbyt2012]

New Video!! Great, thanks. Keep them coming.

[adam917]

Going to get into Imaginary numbers after this? ;-)