Soldato
- Joined
- 29 Jun 2004
- Posts
- 12,954
Hi! I'm just doing a bit of revision. I've got a formula, i've substituted the numbers in i've got one unknown which I need to solve for. I'm usually really good at maths however, this one equation is doing my head in.
0.5 = ( ( 216.7 - 0.0065Z ) / 288.2 ) ^ 5.26
I've taken ln of both sides and divided by the power
( ln 0.5 ) / 5.26 = ln( 216.7 - 0.0065Z ) / 288.2 )
Using log rules ln(x/y) = lnx - lny
( ( ln 0.5 ) / 5.26 ) - ln 288.2 = ln( 216.7 - 0.0065Z )
Eliminating the ln on the right hand side by taking the exp
exp ( ( ( ln 0.5 ) / 5.26 ) - ln 288.2 ) = 216.7 - 0.0065Z
(I'm going to jump a step) And by finally doing a little shuffling
Z = ( ( exp ( ( ( ln 0.5 ) / 5.26 ) - ln 288.2 ) ) - 216.7 ) / -0.0065
This should give me Z to be 5475 but it's not. Can anyone see a flaw in my calculation and tell me where I'm going wrong please!!
0.5 = ( ( 216.7 - 0.0065Z ) / 288.2 ) ^ 5.26
I've taken ln of both sides and divided by the power
( ln 0.5 ) / 5.26 = ln( 216.7 - 0.0065Z ) / 288.2 )
Using log rules ln(x/y) = lnx - lny
( ( ln 0.5 ) / 5.26 ) - ln 288.2 = ln( 216.7 - 0.0065Z )
Eliminating the ln on the right hand side by taking the exp
exp ( ( ( ln 0.5 ) / 5.26 ) - ln 288.2 ) = 216.7 - 0.0065Z
(I'm going to jump a step) And by finally doing a little shuffling
Z = ( ( exp ( ( ( ln 0.5 ) / 5.26 ) - ln 288.2 ) ) - 216.7 ) / -0.0065
This should give me Z to be 5475 but it's not. Can anyone see a flaw in my calculation and tell me where I'm going wrong please!!
