wow, i never knew this would be some advanced university thing....thats why it gave me an headache for 5 hours to try figure it out and still not getting an answer....i was working on inverses of exponentials, trigonometric and logarithimic functions when i hit this question...i was to find the inverse of something similar. I took on firstly interchanging the x and y values....but then when i tried to make the 'y' value the subject of the formula, i just couldn't...

i found this type of question on the Stewart's Calculus 6th Edition....btw, i'm only in year 10 (16 years of age), so i won't know a great deal of things about Lambert and so..but i hope i will get a knowledge of them in these upcoming holidays....

but thanks for you help.