This site makes extensive use of JavaScript.
Please
enable JavaScript
in your browser.
Live
PTR
Beta
Classic
Classic Theme
Thottbot Theme
Drop by and say hi! (Recycle Bin)
Post Reply
Return to board index
Post by
Adamsm
Heh yeah, that was fun for Brewfest.
Post by
438256
This post was from a user who has deleted their account.
Post by
Hyperspacerebel
Clowns are to be feared.
Post by
Hyperspacerebel
Did you ever kiss a llama...
...on the llama?
Post by
Hyperspacerebel
After a series of dejecting scholarship letters, I got some good news and was accepted to UCLA.
Hooray!
Keep your hands off my
sister
cousin!
Well...not really.
Post by
Toldry
Clowns are to be feared.
Y...You...You've never seen that one before?
It's the most popular YTPMV about the Japanese McDonald's clown in existence.
And you haven't seen it till now?
.
.
I am disappoint.
Post by
Hyperspacerebel
Clowns are to be feared.
Y...You...You've never seen that one before?
It's the most popular YTPMV about the Japanese McDonald's clown in existence.
And you haven't seen it till now?
.
.
I am disappoint.
Wait, who said anything about not seeing something before?
Post by
Toldry
You linked as if you're presenting to us something new and original.
And if you think it's new and original you probably haven't seen it before till now.
BAH I HAVE A MATH TEST IN 2 DAYS AND I SUCK AT THE CURRENT MATERIAL.
Post by
Toldry
Some of it is about
this
.
Help me do this question pwease D:
The circumference of a circle is 220 cm. It was divided into 11 arcs which constitute a arithmetic series starting from the smallest arc. The largest arc is 7 times bigger than the smallest. Find the length of the smallest arc.
So:
7a1=a11
7a1=a1+10d
0.6a1=d
S11=5.5=220
61.6d=220
d=25/7
25/7=0.6a1
a1=125/21cm
That's the result that I got. I'm supposed to reach
a1=5cm
Post by
1337Lucius
BAH I HAVE A MATH TEST IN 2 DAYS AND I SUCK AT THE CURRENT MATERIAL.
Maths iz for bads!
Post by
Hyperspacerebel
You linked as if you're presenting to us something new and original.
And if you think it's new and original you probably haven't seen it before till now.
90+% of the things linked here are at least a year old...why are my links any different?
Post by
Hyperspacerebel
Step 4 and beyond should be
S11 = 5.5 = 220
73.3d = 220
d = 3
3 = 0.6a1
5 = a1
Not sure how you got 1.2 and 10.
It's funny, I figured it out on paper in about a minute, then I spent 5 typing it out. Nothing beats using scrap paper for math, heh.
Post by
Toldry
Step 4 and beyond should be
S11 = 5.5 = 220
73.3d = 220
d = 3
3 = 0.6a1
5 = a1
Not sure how you got 1.2 and 10.
I realized a mistake I made, but why 70d/6?
Post by
Toldry
And the formula says theres 2a1 at the start while you put just 1 a1.
:s
Post by
Hyperspacerebel
a11 = 7a1
so if the number right before, 10d/6, is a1, then 7 times it would be 70d/6.
And the formula says theres 2a1 at the start while you put just 1 a1.
:s
Wait, what?
Ugh...I wish I could scan my scrap paper...much easier than trying to format it :P
Sn = (n/2)(a1 + an)
Just plug it in:
n/2 = 11/2 = 5.5
a1 = d/0.6 = 10d/6
an = 7a1 = 7d/0.6 = 70d/6
Post by
Toldry
But a11 isn't used anywhere in the formula.
It's 1+(n-1)d]n/2
Edit: OOOOOOOOOoooooh. I see what you did thar.
You looked at it as if it's 1 + {a1+(n-1)d}]n/2
Smart :o
Post by
Hyperspacerebel
It's 1+(n-1)d]n/2
Why memorize something clunky like that, when there is a much easier way of expressing it?
(n/2)(a1+an)
Post by
Toldry
Thanks HSR, you made me panic a bit less.
Now lets see if I can do the next exercise alone:
A pool that has 900 cubic meters of water got 15 cubic meters of water pumped less every hour than the one before it. In the last two hours 95 cubic meters were pumped.
A. How much cubic meters were pumped at the last hour?
B. How many hours did the pumping last till the pool emptied?
Edit: Nope. I can't.
Post by
Hyperspacerebel
When in doubt, apply brute force.
(I love brute force methods)
A.
Last hour = X
Second to last hour = X + 15
X + X + 15 = 95
X = 40
B.
Write out a list of numbers starting with 40, and increasing by intervals of 15, adding as you go.
When you get to 160, you total should be 900. Now count back how many hours that was.
n = 9
That's the easy, brute force way, and it's also the fastest if you're good at quickly adding numbers.
Here's the actual way:
What do we know?
Sn = 900
a1 = 40
d = 15
What do we need to find out?
n = ?
Let's start with our basic formula
an = a1 + (n - 1)d
an = 40 + 15n - 15
an = 25 + 15n
Let's plug that value into our other equation:
Sn = (n/2)(a1 + an)
Sn = (n/2)(a1 + 25 + 15n)
900 = (n/2)(40 + 25 + 15n)
900 = (n/2)(65 + 15n)
900 = 15n2/2 + 65n/2
1800 = 15n2 + 65
360 = 3n2 +13
0 = 3n2 +13 - 360
Plug that into our quadratic equation:
n = /6
n = (-13 + 67)/6
n = 54/6
n = 9
/wipes brow
Hopefully that's still of some use, even though it's a bit late. Took me a while to type that all out :P
Post by
Toldry
0 = 3n2 +13 - 360
I did it the way you did and got to the exact same result.
But for some reason I seemed to have failed in the quadratic equation part
D:
Post Reply
You are not logged in. Please
log in
to post a reply or
register
if you don't already have an account.
© 2021 Fanbyte
