Author Topic: help please tricky qst for some (Read 1884 times) Tweet Share

lacoste · « **on:** March 21, 2009, 09:17:22 pm »

The parabola has a turning point at (z, −

; it intersects the y-axis at y = 10 and one of
the x-intercepts is x = 5. Find:
a the value of z
b the equation of the parabola.

lacoste · « **Reply #1 on:** March 21, 2009, 09:21:03 pm »

For the parabola whose range is y ≤ 3, whose x-coordinate of the turning point is −4
and whose y-intercept is y = −2 , find:
a the y-coordinate of the turning point
b the equation of the parabola
c the coordinates of the x-intercepts.

Flaming_Arrow · « **Reply #2 on:** March 21, 2009, 09:35:25 pm »

$y=a(x-z)^2-8$

$10=az^2-8$

$\implies a = \frac{18}{z^2}$

$0=a(5-z)^2-8$

$0= a(z^2-10z+25)-8$

expand

$0= \frac{18}{z^2}z^2-\frac{180}{z^2}z+\frac{450}{z^2}-8$

$0 = 10-\frac{180}{z}+\frac{450}{z^2}$

get a common denominator

$-10z^2=-180z+450}$

$0=10(z^2-18z+45)$

$0=10(z-15)(z-3)$

$\implies z= 15$ or $z= 3$

b.

$a = \frac{18}{z^2}$

$\implies a = \frac{18}{9} = 2$

$\implies a = \frac{18}{225} = \frac{2}{25}$

$\therefore y=2(x-3)^2-8$ and $y=\frac{2}{25}(x-15)^2-8$

Flaming_Arrow · « **Reply #3 on:** March 21, 2009, 09:45:32 pm »

a. $y=-a(x+4)^2+3 \ \implies 3$

b.
$y=-a(x+4)^2+3$

$-2=-16a+3$

$a=\frac{5}{16}$

$\therefor y=\frac{-5}{16} (x+4)^2+3$

c.

$0=\frac{-5}{16} (x+4)^2+3$

$-48=-5(x+4)^2$

$\pm\sqrt{\frac{48}{5}}-4=x$

lacoste · « **Reply #4 on:** March 21, 2009, 11:01:09 pm »

why doesnt latex work?

all i see the a box with a red cross in it. when i right click and click show image it doesnt work still

Flaming_Arrow · « **Reply #5 on:** March 21, 2009, 11:03:12 pm »

Quote from: lacoste on March 21, 2009, 11:01:09 pm

why doesnt latex work?

all i see the a box with a red cross in it. when i right click and click show image it doesnt work still

it works for me

pHysiX · « **Reply #6 on:** March 22, 2009, 11:09:16 am »

latex isn't working for me anymore as well >.<

d0minicz · « **Reply #7 on:** March 22, 2009, 02:39:49 pm »

Latex isnt working for me lols

TrueTears · « **Reply #8 on:** March 22, 2009, 02:43:36 pm »

works fine for me

Search the forums now!

We have moved!

Author Topic: help please tricky qst for some (Read 1884 times) Tweet Share

lacoste

help please tricky qst for some

lacoste

Re: help please tricky qst for some

Flaming_Arrow

Re: help please tricky qst for some

Flaming_Arrow

Re: help please tricky qst for some

lacoste

Re: help please tricky qst for some

Flaming_Arrow

Re: help please tricky qst for some

pHysiX

Re: help please tricky qst for some

d0minicz

Re: help please tricky qst for some

TrueTears

Re: help please tricky qst for some

Recent Posts

User:
Password: