Chapter 5 – Quadratic Functions
Dec 7th, 2010 by corricelli
Hello,
Please use this section to post questions/concerns about Chapter 5 homework, quizzes, or tests.
Be sure to put the page number and section of the question you are asking about.
When this starts to get too “busy”, we’ll break it down into sections. If we can get to 20 posts, this will become some IGGI Group Extra Credit! Should this be a goal? What do you think, Team 8??? Can we do it???
Happy blogging,
Mrs. Corricelli
Hi, Mrs. Corricelli, I had a question on problem 91 on the homework. I made the equation (375+x) (240+x) – 90,000 but I wasn’t sure what to equal it to, or if that was even right…thanks!
Hi Mrs. Corricelli, or whoever wants to help, I needed some help on tonights homework, 5.4A, specifically on #s 23 and 24. Do you add the a+bi from the bottom on both sides, or just the bottom? Thanks in advance.
Hello Owen,
You will need to multiply the numerator and the denominator by the same number, so the value of each fraction does not change. The “number” will always be the conjugate of the denominator.
So, for 23, you will multiply the numerator and denominator by the conjugate of 2 – i, which is 2 + i.
So,
[5*(2+i)]/[(2-i)*(2+i)]
=[10+5i]/[4 + 2i - 2i - i^2]
=(10+5i)/(4 – i^2)
=(10+5i)/(4-1)
=(10+5i)/3
= 10/3 + (5/3)i
I hope this helps. In 24, you would multiply the numerator and denominator by the conjugate of 2 + i, which is 2 – i.
Thanks for posting! (and for keeping it complex!)
Sincerely,
Mrs. Corricelli
Hi Ms. Corricelli, I have a question on number 30 for 5.5 b. I know what the pythagorean theorem is but i’m not sure how to bring it in.
ok so we are jst sposed to find X when we solve the equation by completing the square right?
ok nevermind about that last comment i figured it out.
I have another question on #24 tho.
ok so when it has the negative sign do u have to take it out by making the equationL: -1(Xsquared-4X)+3=0 or can you jst leave the negative and solve?
wait not -4X it should be +4X sorry
did anyone else get the answer x=-2+root3 or x=-2-root3???
I dont think you can solve without taking the negative from -xsquared..so you would have to divide both sides by a -1…right?
yeah i think i did it right and i dont think u can have the negative there so yea
okayy!
and what was your starting equation for 29 i think im lost
i dont understand 29 either,i know its something to do with the pythagorian theorem or however u spell it like atticus said but i dont know how to set it up cuz the big trangle isnt a right triangle.
wait no 30 is the pythagorean theorem
do you use it for 29 too…?
i think u could if u had more info but i dont know how to set it up otherwise… i did 30 easy i think
i think u can multiply base times height and set it equal to 23xsquared
wait in 30 do you solve for x or right an equation…or both
then divide by two before u set it equal
find the dimmensions
alrighttt got it
im a little confused wat did u get
Im not sure either on that one but i ended with this (x+2)-11.5
(x+2)squared*
So I stumbled upon this Youtube video today and it’s these two guys rapping about math and all about the quadratic formula and mentioning the discriminant and what not. It also goes into imaginary numbers haha. It’s actually really funny and some people are even saying that it’s helping them remember some things! Just wanted to share it just in case! :]
http://www.youtube.com/watch?v=dBtUetKJzOU&feature=player_embedded