General Homework Help Thread. (Math, Chem, Eng, Hist, Physics, etc)

[event_staff_9]

Welcome to event_staff_9 and spectra's Homework Help Thread!
(hopefully others can help as well!)

We can help with
English
Biology
Chemistry
Physics
Math
US History
World History
Spanish
Statistics
Music Theory
Government (National, State, Local and Comparative)

Evs Specifically Can Help You With:

Biology (up to the Honors Level)
Chemistry (up to the AP Level, although im currently taking it so I may not have learned it yet)
Government (NSL to the AP level, AP Comparative I'm taking now so don't expect too much)
Math (up to Multivariable Calc; again, I'm taking that now, so I may not have learned it yet
Physics (Honors and AP C)
Spanish (up to Spanish 5B or right before the AP level -- I'm a bit rusty however)
Statistics (Up to the AP Level)
World History (Honors Level)
SAT Math

UPDATE: With the return of points, I'd like to mention that I do NOT require nor request point compensation for helping you.

Some Rules:
1. Please try to have at least 100 posts before asking for help. We'll help out anybody but if we're busy, your contributions to M2 will determine how quickly we get to ya.
2. Don't be disrespectful to those helping you. If you don't understand, just ask for more help
3. Don't ask someone to do their entire homework assignment for you. It's for you to learn. By having us do it, you are not learning.
4. Just don't ask for all of the answers from us. Sometimes, we'll guide you through the questions
5. Don't ask us to write essays/do projects for you
6. Don't ask us to read a book for you
7. We have not read every book/learned everything that you may ask. There is a possibility that we cannot answer your question
8. Don't wait till the last minute to give us a question or two. It's only your fault if we can't get by helping you before your test.
9. Don't expect an answer right away. Don't use this as your #1 source; we are humans, we make errors. Use the answers of this thread at your own risk.
10. If you are going to ask a stupid question ex: how do you spell "and" or what's 2+2, don't expect an answer
11. Enjoy learning
12. Do not ask a question you know how to do but don't because you're too lazy. When posting a question, tell us what you tried, what your thought process was.

thanks for adypS for merging the two threads and the mysterious mod who sticked it

[BallinUK]

What is 2+2?

[spankyou]

I seriously needs help on this one


Use the scalar triple product to deternmine whether the points A(1,3,2), B(3,-1,6), C(5,2,0), and D(3,6,-4) lie in the same plane



I got 112, which is a no, and a 0 means yes FYI


P.S.

whoo 3900

[halfHAVOC]

hmm how come
(70 ^ 1/3 ) / (14 ^ 1/3)

the answer is 5 ^ 1/3

but the rule is m - n so why isn't it 5 ^ 0 which is 1 which remains as 5?

or do the 70 and 70 have to be the same ect?

[event_staff_9]

ill answer half-havocs first since there are no calculations involved; i hope im not too late for spankyou; i had just left when you posted :/

anyways, yeah the bases must be the same

correct: x^5 / x ^3 = x ^ (5-3) = x^2

incorrect: x^5 / y ^ 3 does not equal (x/y)^2

working on yours spankyou

edit: okay spankyou, to do a triple scalar product, you'll need to find a determinant of the following matrix of A, B and C:

THIS WAY MAY NOT WORK ALL THE TIME
A(1,3,2), B(3,-1,6), C(5,2,0), and D(3,6,-4)

[1 3 2
3 -1 6
5 2 0]

which is 100

note the numbers of the 3 x 3 matrix above is:

[A1 A2 A3
B1 B2 B3
C1 C2 C3]


next try, A B and D

answer: 100

lets try A, C, and D

answer: 100

how about B, C, and D now

answer: 100

so b/c you had to use triple scalar products and the question asked whether all the points lied in the same plane, and since all the answers are equal its safe to assume that they do

THIS WAY WORKS ALL THE TIME

heres a cooler way using a different formula:

A dot (B x C) (x = cross product) and B dot (C x D)

first you need to make three vectors. AB we'll call vector X = [ 2 -4 4] BC we'll call Y, [2 3 -6] and CD we'll call Z [-2 4 4]

so lets do X dot (Y x Z) first:

B x C = [12 20 14] dot it with A and you get 0! so A B and C are coplanar

so lets try Y dot (X x Z) X Z is [0 0 0] so the dot product must be zero! yipee! we found that A B and C lie in the same plane and B C and D also do therefore all four lie on the same plane!

[spankyou]

Originally Posted by event_staff_9

ill answer half-havocs first since there are no calculations involved; i hope im not too late for spankyou; i had just left when you posted :/

anyways, yeah the bases must be the same

correct: x^5 / x ^3 = x ^ (5-3) = x^2

incorrect: x^5 / y ^ 3 does not equal (x/y)^2

working on yours spankyou

edit: okay spankyou, to do a triple scalar product, you'll need to find a determinant of the following matrix of A, B and C:

THIS WAY MAY NOT WORK ALL THE TIME
A(1,3,2), B(3,-1,6), C(5,2,0), and D(3,6,-4)

[1 3 2
3 -1 6
5 2 0]

which is 100

note the numbers of the 3 x 3 matrix above is:

[A1 A2 A3
B1 B2 B3
C1 C2 C3]


next try, A B and D

answer: 100

lets try A, C, and D

answer: 100

how about B, C, and D now

answer: 100

so b/c you had to use triple scalar products and the question asked whether all the points lied in the same plane, and since all the answers are equal its safe to assume that they do

THIS WAY WORKS ALL THE TIME

heres a cooler way using a different formula:

A dot (B x C) (x = cross product) and B dot (C x D)

first you need to make three vectors. AB we'll call vector X = [ 2 -4 4] BC we'll call Y, [2 3 -6] and CD we'll call Z [-2 4 4]

so lets do X dot (Y x Z) first:

B x C = [12 20 14] dot it with A and you get 0! so A B and C are coplanar

so lets try Y dot (X x Z) X Z is [0 0 0] so the dot product must be zero! yipee! we found that A B and C lie in the same plane and B C and D also do therefore all four lie on the same plane!

very very interesting

you see I did vector AB, AC, and AD instead

so I was off right at the start

I turned in the HW at 3 today.. 10 minutes before you submitted yours

so that one I got wrong, but it's all right, thank you for the explaination, are you in college or something?

[event_staff_9]

Originally Posted by spankyou

very very interesting

you see I did vector AB, AC, and AD instead

so I was off right at the start

I turned in the HW at 3 today.. 10 minutes before you submitted yours

so that one I got wrong, but it's all right, thank you for the explaination, are you in college or something?

oh damn sorry lol; stupid school always get in the way of my schedule haha

im a junior in high school; my math and physics grades arent good but i understand the concepts i guess (i hope at least -- AP exams in May lol); i get the basic idea for most of this stuff, but sometimes i look on the web to refresh my memory. not the smartest kid (not even close) on the block but i try to be the most helpful

[spectra]

Originally Posted by halfHAVOC

hmm how come
(70 ^ 1/3 ) / (14 ^ 1/3)

the answer is 5 ^ 1/3

but the rule is m - n so why isn't it 5 ^ 0 which is 1 which remains as 5?

or do the 70 and 70 have to be the same ect?

lets say you have

x^4 and y^3

you can't just add/subtract them

you need to have the same base

x^4/x^3 = x

Originally Posted by Multi surface polish

What is 2+2?

The answer is 7 duh. What type of dumb question is that

[BallinUK]

Originally Posted by spectra

The answer is 7 duh. What type of dumb question is that

Finally someone answers me. I've been struggling with this homework for ages.


Oh Mrs Pickybitch will be pleased.

[event_staff_9]

loll ^^

just a side note, ill be a lil busy around 10ish (about an hour an half from now) but you can post anyway and ill check the thread

also, im going college visiting spring break which starts friday so ill be out a couple days here and there. no more than 2 days at a time

edit: 11:35- tuning out for the night guys; if you guys have any questions ill try to get to them during school but ill probably respond around 4-ish tomorrow