View Full Version : How do I solve this?
qtiphife
Oct6-04, 02:55 PM
X-(S+P-C)E^RT+D*E^RT=0
How can I "isolate" C?
Thanks
Assuming E^RT means E^(RT)...
X - (S + P - C)E^(RT) + D*E^(RT) = 0
<=>
X + D*E^(RT) = (S + P - C)E^(RT)
<=>
X/E^(RT) + D = (S + P - C).
Etc.
Tom Mattson
Oct6-04, 03:09 PM
qtiphife,
Please post your questions only once. Triple posting is considered spam.
Thank you,
qtiphife
Oct6-04, 03:09 PM
So would this be X/E(RT)+D-S+P= C
Man I am terrible with math.
Tom Mattson
Oct6-04, 03:11 PM
So would this be X/E(RT)+D-S+P= C
Close. It should read:
X/E(RT) + D - S + P = -C
You forgot the negative sign.
Divide both sides by -1, and you're done.
qtiphife
Oct6-04, 03:12 PM
Oh yeah, and (rt) have different "T's". Thanks.
Integral
Oct6-04, 04:13 PM
TIME OUT!
are you saying that in you original realationship that the T is not the same in the 2 expressions where it is used?
X-(S+P-C)E^RT+D*E^RT=0
Do you actually mean
x - (s+ p - C) e^{Rt} + D e^{RT} = 0
If so then
C = x e^{-Rt} + D e^{R(T-t)} - S +P
qtiphife
Oct7-04, 08:49 AM
Guys, thanks a ton for your help, however I am still not getting the correct answer. Here are what the letters stand for:
X (Strike Price)= 50
S (Price of underlying) = 51
P (price of put)= 2.125
e (euler's number) = 2.781
R (rate of interest)= .08
t (time until options expire)= 31/365
T (time until dividend paid)= 25/365
D (dividend)=.46
C (price of call) = ??????????
I keep on getting a negative number. Any help would be much appreciated. Thanks.
Integral
Oct7-04, 09:28 AM
It would be more helpful if you were to give the physical signifcance of the equation and parameters. Where did you get it? What is it for? Why can't C be negative?
qtiphife
Oct7-04, 09:33 AM
Sure,
This formula represents a stock's value with dividend due to the put call parity (kind of a pain to explain), but it has to do with buying or selling a stock (underlying) and buying (selling) and selling (buying) options in order to hedge your position in order to create "edge". X represents the strike price the options are bought, and P is the value of the put and C is the value of the call. I need to know the value of the call.
Please look at my previous post for all of the information.
Thanks!
Gokul43201
Oct7-04, 03:56 PM
In your previous posts, you only talk of one T. Now there's two : t and T. So, which is which ?
One more thing. Everyone seems to have copied and repeated a line you wrote, with an uncorrected error :
Post #4 : "So would this be X/E(RT)+D-S+P= C"
Besides, the negative C correction, note that the LHS should really be X/E(RT)+D-S-P. Minus P, not plus.
Integral
Oct7-04, 04:08 PM
Opps! :redface:
You would and should come up with a negitive number, since I lost a negative sign! Try this:
C =S+P- x e^{-Rt} - D e^{R(T-t)}
My apologies for the sloppy algebra!
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