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Question
hi,

I'm doing an exponential regression in excel and have been given this equation. y = 1E-19e^1.9985x
i know the 1E-19 is ten to the minus nineteen and i believe the e represents an exponential constant.

say i had an x value of 23, i don't suppose there is a chance you would know how to type this full equation into excel to work out the y i can't seem to make it work. i am hopeful your mathematical brain might fare better.

cheers

Answer
The expression can be written in Excel notation as

y = 10^(-19)*EXP(1.9985*x)

where EXP is an actual function in Excel that expects an argument (i.e., some number or cell reference) inside the parentheses.

The ∧ in the expression 10^(...) just means "raise to the power" e.g.. 10 squared would be 10∧2.

Putting the number 23 into the symbol x is a 2 step process. First put the number 23 into some convenient cell, like C1 (3rd column, first row). This can then be referenced as $C$1, where the $ means always refer to the specific column or row.

so, if you want the value of y to be evaluated in the cell A1, then put into that cell the expression

= 10^(-19)*EXP(1.9985*$c$1)

where the "=" sign is included (in fact, it is very important to put the = sign in there so that Excel interprets what's in the cell as an expression it needs to evaluate). Copying directly from the Excel file I used, the expression for y in the cell A1 is

=10^(-19)*EXP(1.9985*$C$1)

and the number it produces is

9.174090245

where I put 23 into the cell C1.

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