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pooja195 (pooja195):
@mathmate
pooja195 (pooja195):
Chapter 9 ;-;
OpenStudy (mathmate):
Chapter 9
======
OpenStudy (mathmate):
|dw:1433627905280:dw|
Find x (hypotenuse) shown in the above drawing.
pooja195 (pooja195):
a^2 + b^2 = c^2?
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OpenStudy (mathmate):
Yep, now evaluate x numerically, please.
pooja195 (pooja195):
12^2+5^2=c^
144+25=169
13^2
OpenStudy (mathmate):
So x=13 (is the final answer).
OpenStudy (mathmate):
which two consecutive integers does sqrt(200) fall between?
pooja195 (pooja195):
idk this ;-;
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OpenStudy (mathmate):
10^2=100
11^2=121
12^2=144
13^2=169
14^2=196
15^2=225
16^2=256
...
which two consecutive integers does sqrt(200) fall between?
pooja195 (pooja195):
no .-.
pooja195 (pooja195):
*none
OpenStudy (mathmate):
"between" is the keyword.
We know that 14^2=196, and 15^2=225
or sqrt(196)=14, sqrt(225)=15, so sqrt(200) falls between which integer numbers?
pooja195 (pooja195):
Decimals? .-.
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pooja195 (pooja195):
wait no
OpenStudy (mathmate):
no, we are looking for two integer numbers! lol
pooja195 (pooja195):
This si confusing T_T lets skip this
OpenStudy (mathmate):
the answer is 14 and 15.
In fact sqrt(200)=14.1421356237309.... (never ends).
So we know that sqrt(200) falls between 14 and 15!
You were probably thinking that it's more complicated than this!
pooja195 (pooja195):
-_-
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OpenStudy (mathmate):
The hint is 14^2=196, so too small,
15^2=225, so too big.
Therefore sqrt(200) must fall between 14 and 15. Is that ok?
pooja195 (pooja195):
yes
OpenStudy (mathmate):
Solve the equation 27-3y^2=0
pooja195 (pooja195):
Would you like the work or is it ok to put in the answer?
OpenStudy (mathmate):
put in the work, but LaTeX is not required.
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pooja195 (pooja195):
first find a GCF
27-3y^2=0
-3 is the gcf
then square root
answer: −3(y+3)(y−3)
set values to 0
y=3 or y=−3
pooja195 (pooja195):
/.\
OpenStudy (mathmate):
Very good, shows that you're comfortable with factoring.
It will help in the later sections.
You can also solve by isolating y,
-3y^2=-27
y^2=9
y=\(\pm 3\)
OpenStudy (mathmate):
Ready for the next one?
OpenStudy (mathmate):
an engineering student is a contestant in an egg dropping contest. The goal is to create a container for an egg so it can be dropped from a height of 32 feet without breaking. The model for the egg's height, h (in feet), at time t seconds since release, is
h = -16t^2 + 32.
Calculate the time at whic the egg is at a height of 10 feet above ground. Give answer to 2 decimal places.
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pooja195 (pooja195):
10=-16t^2+32
subtract 32 from both sides then divide by 16
1.375= t^2
idk where to go after this
OpenStudy (mathmate):
Take out your ti-83 to finish!
OpenStudy (mathmate):
"give answer to 2 decimal places" is a hint you might need your ti-83!
OpenStudy (mathmate):
sqrt(1.375)=?
pooja195 (pooja195):
1.172604
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OpenStudy (mathmate):
exactly! (1.17 for 2 decimal places).
OpenStudy (mathmate):
Any questions before we move to simplifying radicals?
pooja195 (pooja195):
no
OpenStudy (mathmate):
Simplifying radicals basically is to pull things out of the square-root sign, whenever possible.
For example, sqrt(4)=2 is rather straight-forward.
OpenStudy (mathmate):
But sqrt(18) is less obvious, since we write
sqrt(18)=sqrt(3^2 *2)=3sqrt(2)
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OpenStudy (mathmate):
So I'll let your try sqrt(48) while I take a meal break!
pooja195 (pooja195):
48
6 8
3 2 42
\[2\sqrt{12}\]
OpenStudy (mathmate):
almost, just one step further
sqrt(48)=sqrt(4*12)=sqrt(16*3)=sqrt(4^2 * 3)=4sqrt(3)
OpenStudy (mathmate):
Simplify
(1) sqrt(98) [98=2*7*7]
OpenStudy (mathmate):
So every factor that appears twice inside the radical you take one outside.
So sqrt(98)=sqrt(2*7*7)=7sqrt(2)
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pooja195 (pooja195):
Dance club.
pooja195 (pooja195):
Dance club is the method my teacher taught me because teens like to think like that
OpenStudy (mathmate):
Oh! Can you show me that?
pooja195 (pooja195):
Ok its been a while but eh :P
56
8 7
4 2
2 2
2 and 2 are a couble so they leave the dance club
2 squrt 2
idk if its right
OpenStudy (mathmate):
Yes, I get the part for the leaving dance club part (ingeneous!)
Then we have to keep 2*7 in the club, so we get
2sqrt(14)
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pooja195 (pooja195):
lel :3
pooja195 (pooja195):
Are we done with this section ?
OpenStudy (mathmate):
I usually like to see you do at least one perfect answer, like
(2) sqrt(60) [60=2*2 * 3 * 5]
then there is rationalize the denominator.
pooja195 (pooja195):
T_T
pooja195 (pooja195):
ok
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OpenStudy (mathmate):
(2) sqrt(60) [60=2*2 * 3 * 5]
pooja195 (pooja195):
im confused whats the question? .-.
OpenStudy (mathmate):
simplify sqrt(60)
pooja195 (pooja195):
60
10 6
5 2 3 2
2 sqrt 15
pooja195 (pooja195):
T_T say im right!
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pooja195 (pooja195):
Princess demands it!
OpenStudy (mathmate):
Yes, you're right, I don't think you have problem with that.
OpenStudy (mathmate):
Now we move onto rationalizing the denominator.
OpenStudy (mathmate):
Mathematicians traditionally do not like to see square roots in the denominator, because that would make the common denominator very messy.
pooja195 (pooja195):
Just multiply by the root
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pooja195 (pooja195):
*in the denominator
OpenStudy (mathmate):
Do you want me to explain, or jump to pretest?
pooja195 (pooja195):
Pretest
OpenStudy (mathmate):
Rationalize 9sqrt(1/3)
pooja195 (pooja195):
9 squrt 3
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pooja195 (pooja195):
^LOL
OpenStudy (mathmate):
Sure?
OpenStudy (mathmate):
The question was \(9\sqrt{\frac{1}{3}}\)
pooja195 (pooja195):
:/
pooja195 (pooja195):
this is diffrent .-.
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