20S pre-cal

Thursday, March 02, 2006

Scribe post

Well thanks a lot Wendy I' didn't want to be scribe you will regret it in the future hahaha.
Today in class we talked about how to write the equation of a straight line.
There are two ways that this can be determined
1) slope intercept form
y=mx+b "m" is the slope and "b" is the y-intercept
2)Point-slope form
y-y1=m(x-x1)
We also learned that there are three different ways to show the equation
the slope-intercept form,the general form, and the standard form.
y=3/2=6--->y=mx+b
2)3x-2y=6 ---->ax+by=c this is the general form
3)3x-2y-6=0--->ax+by+c=0 this is standard form
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After learning that we did a few review questions on slope-intercept form
1)m=2 b=6 -->y=2x+6 2)m=3 b=38-->y=3x+38 3)m=-17/5 b=163-->y=-17/5+163
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After that we did a few examples using the point-slope form y-y1=m(x-x1)
ex.1 given A(3,-2) and m is -3/5
you substitute what you know into the equation
y-(-2)=-3/5(x-3)
then you multiple everything by 5 to get rid of the fraction
(5)(y+2)=(5)-3/5(x-3)
=5y+10=-3(x-3)
=5y+10=-3+9
=5y=-3x+9-->3x+5y=-1-->ax+by=c general form or 3x+5y+1=0 standard
then divide everything by 5 to get y by itself
=5y/5=-3/5-1/5
=y=-3/5-1/5 this is the slope-intercept form

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In the second example we had solve the equation by using the x-intercept and we had to find the three ways to write the equation of a line

x-intercept=3 m=2
(3,0)
y-y1=m(x-x1)
y-0=2(x-3)
y=2x-6 -->y=mx=b
-2x+y=-6-->ax+by=c
-2x+y+6=0-->ax+by+c=o
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ex.3
In the last one we were allowed to put it into any form that we wanted I chose the general form
p(-3,7) m=-7/2
y-7=-7/2(x-(-3))
(2)y-7=(2)-7/2(x+3)
2y-14=-7(x+3)
2y-14=-7x-21
7x+2y=-7

we worked on ex.13 today and omitted 13,14,17
And tomorrow's scribe is SUPER buTT

1 Comments:

  • At 8:58 PM, March 02, 2006, Blogger Wendy_V said…

    good job natasha. i really thought you weren't going to do it. well im happy for you that you did it though because... it would of been a bummer if yyou didn't do it! =). im sorry for making you the scribe but you got to understand that you were basically one out of 15-20 people that actually know how to scribe and we would give a good example to our fellow class mates what we're suppost to do for scribeing. thank you very muchhh natasha. your good friend. me =)

     

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