Seeking advice while preparing for a course.

[Iccanui]

Hi.


I have signed up for the introduction to astronomy course at coursera.

https://www.coursera.org/course/introastro

Video describing course http://youtu.be/lOmXPQtQzC8

In the suggested background section it suggests "A familiarity with the rudiments of high-school algebra " . Unfortunately my schooling did not involve algebra at all. I am trying to remedy this in the 3 months i have before the course starts by using Khan Academy to bring my math skills up to speed. I am already starting to do decimal division and multiplication and am just about to start exponents, which is the first example of math needed. I am finding this stuff is mostly review so far thankfully. But the formula example in the second part looks more advanced and unfortunately i have no memories to pull from.

If you could please look at the attachment image and look at example 3 which starts with the words " A familiarity with the rudiments of high-school algebra, the ability to solve an equation like..." and let me know how deep this is i would be grateful. I am worried that 3 months might not be enough to get up to that level. I am wondering what the path is from finding composite and primes, multiplication and division of decimal numbers, basics on exponents, positive and negative numbers, which is all arithmetic and pre-algebra according to Khan and the math needed for this course. How far do i have to go?

I have also signed up for a Introduction to Mathematical Thinking course at coursea as prep for the Astronomy Class. This course starts sep 17th and i figure that even if i can't pass it, learning how to think about math in a more advanced way, will be nothing but a benefit.

Mathematical Thinking http://www.coursera.org/course/maththink
Intro Video http://youtu.be/YFs06zgBfMI

Hope I am not trying to reach too far too fast.

Thank you for any responses.

 

[kaiten]

hmm... i would probably focus more on getting your algebra down than getting super good at arithmetic. assuming you can add/subtract/multiply/divide numbers just fine, next you should gain some familiarity with exponents (more about understanding how they work than about actually calculating a lot of them). and then jump right into algebra and get as much practice as you can.

edit: you should also get some familiarity with "scientific notation" since its useful for dealing with really big and really small numbers. this can be done before, after, or during your algebra practice.

as far as algebra goes, i think getting used to using variables and performing various manipulations will prove more useful than trying to perfect specific techniques or focusing too much on specific types of problems, so once you can get a little comfortable with using variables and solving the most simple equations (linear equations) you might want to jump around a bit trying little bits of everything or even making up random problems to try and solve instead of watching 35 videos about quadratics or something like that (quadratics are useful and good to do after linear equations but watching all 35 vids they have at kahn academy is overkill since you probably won't need them much for this course).

more specifically about this course (which I'm considering taking myself) the example equation looks more complicated than it actually is since you can solve it (for D) by just multiplication/division and taking a cube root at the end (though i imagine it looks like complete nonsense if you're not used to equations with more than 1 variable)

also, when solving algebraic equations, you're doing anything you can to get the variable you're solving for to be all by it's self on 1 side of the equals sign, and anything else on the other side. this will be the goal no matter how complicated the problem looks. so if you want to solve something like "2x+4=6" for x you need to somehow get rid of the 2 and 4 so x will be by its self. if you subtract 4 that will get rid of the 4, but since you need to keep both sides of the equals sign equal, you need to subtract from both sides giving 2x+4-4=6-4 which simplifies to 2x=2, now to get rid of the 2 you can divide by 2, and again, to keep both sides equal you have to do it to both sides so (2x)/2=2/2 which simplifies to x=1. more concisely thats:

2x+4=6
subtract 4 from both sides
2x=2
divide both sides by 2
x=1

a seemingly more complicated example: solving something like "ax+by=c" for x is really the same thing even though it has all these other variables there

ax+by=c
subtract "by" from both sides
ax=c-by
divide both sides by "a"
x=(c-by)/a

being able to do stuff like that is pretty much the bare minimum before you can say you've learned some algebra but its a good starting point i think. if what i did above makes any sense to you (i didnt explain in much detail, and i jumped the difficulty up with no warning, so don't worry if it doesnt) then getting to a sufficient skill level shouldn't take too much longer.

finally, when you're stuck for a long time something like www.wolframalpha.com can be your best friend. it can solve just about anything if you ask it correctly and will usually have a "show steps" button to show hot it was done.

 

[Iccanui]

Thank you so much for the time you took to answer me. It helped a lot on plotting my course. :)