Thursday, August 14, 2008

8/13 SAT WORK (Session 1)

BOOK: The Official SAT Study Guide: For the New SAT

SCORES:
-Section 1: 18/20
-Section 2: 14/16

I spent some more time on each section and i made sure i had no careless mistakes!

INCORRECT ANSWERS:
-Section 1:

1. If y=(5x^3)/z, what happens to the value of y when both x and z are doubled?
* y in not changed
*y is halved
*y is doubled
*y is tripled 
*y is multiplied by 4

My answer was the 'y is doubled' because i used my own numbers for x and z. x= 2 and x=4, therefore making y=5(x^3)/z equal 10. Then the new equation was 5x^6/z^2 and i got 20. I know i shouldn't put in my own numbers but how else would you know what happens to y?

2. In the figure above, three wires are braided. That is, by starting in the order A, B, C, the outer left wire A is brought over wire B to the middle position, forming the order shown in step 1, then the outer right wire C is brought to the new middle position shown in step 2 and so on, alternately bringing each new left  and each new right wire to the middle. At what numbered step does the braid first repeat the original order A, B, C?

My method was more hands on.... i braided my own hair and got 5.

The answer was 6 .____. I guess my method should die.

-Section 2

1. g(n)=n^2+n
   h(n)=n^2-n

*g(m)
*g(m)+1
*g(m)-1)
*h(m)+1
*h(m)-1

Which of the following is equivalent to h(m+1)?

I don't understand this problem. i do not even see the variable m in the equations given, so i feel like its really random and could mean any number.

2. In rectangle ABCD point E is the midpoint of line BC. If the area of quadrilateral ABED is 2/3 what is the area of rectangle ABCD?

*1/2
*3/4
*8/9
*1
*8/3

I thought this was a trick question so i put 1 down because it's 2/3's of the rectangle..

& sorry for the bootleg pictures.
my camera is spazzing and is like broken
it's a camera picture

1 comment:

KVK said...

Opal,

Nice work on careless mistakes. Very impressive. You are scoring much better on these sections than you were before.

1) you can plug in numbers, but you did it wrong. The variables are doubled, not the exponents. So the correct way to set up the new equation is:

5*((2x)^3)/(2z)

This is pretty much a careless mistake. No worries.

2) Opal, its a pattern with a low number. Just work it out to see when it repeats, and test it. Don't try to get clever by doing it with your own hair-- its hard to count how many you've done with your own hand when its behind your head. Do it on paper next time. Again, careless mistake.

3) First, what is h(m+1) equal to?
Dude, you don't get functions at all. You need to read as much as you can EVERYWHERE to get them. the letters don't mean anything.

if I tell you that h(x)=x+1, that means that the function H takes any variable within the parenthesis and adds 1.

That means that h(1) is 2, h(q) is q+1, and h(a;sdlkjf;ads) is a;sdlkjf;ads + 1

h(2100^2-12312)= 2100^2-12312 + 1
h(opal) = opal + 1
h(kapil)= kapil + 1

then, lets take another function Q. Define it as q(x)= x^2

this means that
q(opal)= opal^2
q(a;slkdfj) = as;dljf^2
q(53)=53^2

then you can combine functions

what is q(h(x))?

you just do those functions to X from outside in

h(x)=x+1
q(x+1)=(x+1)^2

q(h(5))= q(6) = 36

q(h(opal))= q(opal+1) = (opal+1)^2

You get it?

so in this situation, h(n)= n^2-n. h(m+1)= (m+1)^2-(m+1). That simplifies to m^2+2m+1-m-1,

m^2+m

that is the same as g(m), because g(m)= m^2+m

4) here, pretend that the quadrilateral is a square. Draw it out. The answer becomes readily apparent: the smaller inside shape is 3/4 the size of the total shape.