Want to get better at algebra

jwzumwalt

New member
Joined
May 20, 2018
Messages
2
I am a 60yr old retired engineer/programmer and have always wanted to know math better. I now have the time to spend on it.

1) I am currently working with relatively simple aerospace formulas that I need to rearrange the equations and would like some comprehensive reference with lots of examples that go from simple to complex. A typical formula might be[FONT=&quot] tan(b)= v^2/(Rxg) and I will need to re-arrange for each variable. Other formulas include sq root, etc.[/FONT]

2) I would also like to use a free online course for advanced algebra, or better yet a comprehensive set of YouTube videos. I would be very grateful for any suggestions- thx.
 
I am a 60yr old retired engineer/programmer and have always wanted to know math better. I now have the time to spend on it.

1) I am currently working with relatively simple aerospace formulas that I need to rearrange the equations and would like some comprehensive reference with lots of examples that go from simple to complex. A typical formula might be tan(b)= v^2/(Rxg) and I will need to re-arrange for each variable. Other formulas include sq root, etc.

2) I would also like to use a free online course for advanced algebra, or better yet a comprehensive set of YouTube videos. I would be very grateful for any suggestions- thx.
Welcome....

Two of the resources:

purplemath.com

KhanAcademy videos

There are some simple strategies for "isolating" variables.

For example:

tan(b)= v^2/(Rxg) ........................... and you want to solve for 'v' (make 'v' the dependant variable).

Are you using 'x' for multiplication sign - or another parameter? Do not use it as multiplication sign for these forums. It gets confused with 'x' as variable. I am going to assume here that 'x' is a variable.

Rewrite the equation such that all the terms containing 'v' is on one side of the "=" sign - rest on the other side.

To do that here - we multiply both sides by (Rxg) - here assumption is that 'Rxg' is NOT equal to zero. Then we get:

tan(b) * (Rxg)= v^2/(Rxg) * (Rxg)

tan(b) * (Rxg)= v^2/(Rxg) * (Rxg)

eliminating dividing and multiplying by (Rxg) on the right hand side (RHS) of the equation, we get:

tan(b) * (Rxg)= v^2

Now we need to reduce RHS to 'v'. Taking square-root of both sides

\(\displaystyle \sqrt{tan(b) * (Rxg)} \ \ \) = v

There - you have it.

This process will not work "exactly" for all the equations - but the philosophy will work most of the time.
 
Thanks "Subhotosh Khan" for the help, the formula was a quick cut and paste and should have been tan(b)= v^2/(R*g)
I have some notes for the basic stuff but where I get in trouble is when the equation has powers, sqr-root, and or part that is divided and part that is not.

I actually am designing (and writing JS routines) for an experimental aircraft and would like to calculate performance relationships/options but I am as much interested in learning HOW to do the math as I am in getting the answer. I taught high school physics for a couple years but all the formulas where already given and there was never a need to re-arrange anything.

I found a couple sites that would automatically solve but they don't show the steps and sometimes the answer is also wrong! If I could find 15 or 20 examples somewhere, I am pretty shure I could figure things out.

The actual formula that I am working on right know is A = k*(S*c / d))
where:
A = horz tail surface
k = coefficient (.6 to 1.2)
c = wing chord
S = wing area
d = cg to tail distance

In this example I am most interested in k, but there is a division in the middle and I get stuck. My guess is I first need to divide by k...
A = k*((S*c) / d))
-- -------------
k k

or maybe it should be...
A k * (S*c / d))
---------- = --------------
S*c / d S*c / d


then what???

-------

Below is the only cheat sheet I have

[FONT=&quot]Solving for Squares & Roots
[FONT=&quot] [/FONT]
[FONT=&quot]B[/FONT]​
[FONT=&quot]A = ---[/FONT]​
[FONT=&quot] C2[/FONT]​
[FONT=&quot] [/FONT]
[FONT=&quot]Is the same as,[/FONT]

[FONT=&quot] [/FONT]
[FONT=&quot]B[/FONT]
[FONT=&quot]C2 = ---[/FONT]
[FONT=&quot] A[/FONT]​
[FONT=&quot] [/FONT]
[FONT=&quot]Is the same as,[/FONT]

[FONT=&quot]c = sqrt(b/a)[/FONT]


[/FONT]
 
Top