1

I got this formula for calculating-

100x(EXP.((17.625x32)/(243.04+32)/EXP.((17.625x54)/(243.04+54)))=?

The answer should be 43, but I Keep getting 65. Please, can anyone calculate this correctly?

Thank You!

Rena
  • 11
  • 2
  • Thanks, but no since I got the right formula, but I am having trouble doing math. I really need help to calculate with correct steps to get 43. – Rena Oct 04 '21 at 15:51
  • I get 64. Are you sure you have the equation correct? – Fred Oct 04 '21 at 16:51
  • Yes, the equation is correct. I use Exponential function incorrectly. I know that it is 2.71828 constant, but still get the wrong answer. – Rena Oct 04 '21 at 17:25
  • @Jean I think the best link would really be this one – JeopardyTempest Oct 04 '21 at 18:49
  • It'd be best to say where you got the formula, so it's correctness can be better verified and mistakes more easily noticed? – JeopardyTempest Oct 04 '21 at 18:50
  • Guessing from the numbers you use (32 and 54?), multiple RH calculators show that RH should be 44% if in Fahrenheit, or 31% if in Celsius, so it does seem the formula\usage is in err. – JeopardyTempest Oct 04 '21 at 19:01
  • If your source was indeed Relative Humidity approximation from Dew Point and Temperature, I'm a bit suspicious of the author's "update", as it's not explicitly given in the paper. However, it appears from skimming the paper that the formula likely should be using Celsius, so if you're in Fahrenheit, that may be a source of issues – JeopardyTempest Oct 04 '21 at 19:06
  • If your issues are using their equation, next time please post a comment to their question (I'm not sure if you can with no reputation, but if you keep using StackExchange, you will be able to soon) or in Chat. – JeopardyTempest Oct 04 '21 at 19:07
  • Your parentheses above look wrong, it would put the second EXP inside the first, rather than doing two separately. It does look like if you follow the layout of the linked RH question just above, it gives the correct answer (32% for the given numbers in Celsius). (Convert to Celsius before using the equation if in F to get right answer) – JeopardyTempest Oct 04 '21 at 19:18
  • @JeopardyTempest Actually the oldest seems to be this one: https://earthscience.stackexchange.com/q/14899/18081 Anyway, the question has been asked (and answered) multiple times. – Jean-Marie Prival Oct 04 '21 at 20:04
  • But he wants to calculate RH not temp/dew point, so although they're related my link is a lot more direct... plus the formula looks to come from the question I link to :-) – JeopardyTempest Oct 04 '21 at 21:30
  • Solved it already in a different way! Thanks for responding though! – Rena Oct 04 '21 at 23:30
  • 1
    @Rena the goal of the site is to provide one's learning for the next person to benefit from. So if it was something useful, perhaps post it as an answer here or on the Relative Humidity approximation from Dew Point and Temperature question so others can benefit. Generally questions with a user-centric bug is being made get closed and no answers because they aren't of use to a larger group... but I tried to be of help. Seems the least you could do is tell us what changed :) – JeopardyTempest Oct 05 '21 at 02:18

0 Answers0