Need help rearranging an equation

[Marked 197]

Hey guys,

 

I got a finance assignment due tomorrow at 5pm and I gotta show some algebraic rearranging. I've got the equation to start out with and what you have to end up with, but I just need the steps in getting to that point...

 

Here it is, rearrange to find r₀

[kellessdee 48]

wow, I am so GLAD I didn't go for finance.

 

I've been trying to work this out, and I just can't get it. This hurt my algebra-esteem :(

 

I even tried working backwards from the end, to get to the start. Either this is terribly contrived, or I was never as good at algebra as I thought. Or it's some kind of financial mathematical formula.

 

For some reason, any kind of financial math makes me wither up and die inside. My last math course, the midterm (all computer math) I got 100%, the final exam (mostly financial math) I got 50%.

 

I don't even get it, it's all math, but for some reason my brain just doesn't like monetary formulas.

[Moonpearl 32]

Goooot it!

 

Just to say, I've never done math in English, so I'll be using the words that seem appropriate to me, I hope it all makes sense.

 

Base expression

r(s) = r(0) + D/E * ( r(0) - r(D) ) * (1 - t© )

 

First distribute (D/E) over ( r(0) - r(D) )

r(s) = r(0) + ( D/E * r(0) - D/E * r(D) ) * (1 - t© )

 

Then distribute (1 - t© ) over ( D/E * r(0) - D/E * r(D) )

r(s) = r(0) + D/E * r(0) * (1 - t© ) - D/E * r(D) * (1 - t© )

 

Then factorize by r(0)

r(s) = r(0) * (1 + D/E * (1 - t© ) ) - D/E * r(D) * (1 - t© )

 

Add D/E * r(D) * (1 - t© ) to both sides

r(s) + D/E * r(D) * (1 - t© ) = r(0) * (1 + D/E * (1 - t© ) )

 

Divide both sides by (1 + D/E * (1 - t© ) )

(r(s) + D/E * r(D) * (1 - t© ) ) / (1 + D/E * (1 - t© ) ) = r(0)

 

This is your goal expression (even though it's much less readable, but you can trust me on this one).

 

Feed me with more equations anytime.

[kellessdee 48]

I just +1'd you

 

Because I really wanted to know what I was doing wrong :D

[Marked 197]

Yay! Thank you so much! Now I don't have to worry about my finance tomorrow and can spent the whole day writing my other assignment.

 

This isn't as bad as I thought it would be. I've learned all that stuff but I probably wouldn't have remembered enough to do the last 2 steps. Probably woulda forgot I could factorize. I actually forgot to take a pen and paper to uni today so I didn't attempt it.

 

 

wow, I am so GLAD I didn't go for finance.

This is a final year course called advanced corporate finance but its not so bad. I wrapped this assignment up in 2 days and as you may have gathered the algebra isn't a very big part. I did this assignment 2 weeks in advance and had to email my lecturer whether it was even required, and it was. Duno why you'd get marks for rearranging in an assignment because you can cheat, like me :) Thanks for trying for me also

[Jon Bon 43]

Moonpearl, you're a monster, no a machine. You never cease to impress me, and that's a hard feat. Good job on this mate, kudos!

[Moonpearl 32]

Moonpearl, you're a monster, no a machine. You never cease to impress me, and that's a hard feat. Good job on this mate, kudos!

Well, math is tricky because looks are deceiving. When it looks easy, it's often complicated in actuality, and vice-versa. What gets people stuck on such a problem is not its intrinsic difficulty, but rather, that they freak out and persuade themselves they can't do it before even trying. If you set aside the fact that this equation rearrangement looks difficult and try to solve it as though it was 2x + 3 = 5, it's actually very easy (technically speaking it's middle school level - not to offend anyone, I mean everyone gets stuck on simple problems, it's well known that humans create their own difficulties sometimes).

 

And giving some math teaching in real life serves me well I guess.