Thread: ln equation

Hello, my attempt at solving this equation:

'10000 = 250e^(t*ln2)' for t comes out at:

ln40/ln2.

However my textbook says the answer is ln4/ln2.
Can someone please confirm which one it is.

Thanks kindly

Originally Posted by fran1942

Hello, my attempt at solving this equation:

'10000 = 250e^(t*ln2)' for t comes out at:

ln40/ln2.

However my textbook says the answer is ln4/ln2.
Can someone please confirm which one it is.

You are correct. And anyway, if the answer was , that would simplify to just 2 (from the change of base formula):

,

and 2 definitely isn't the solution.

Edit: Make sure you copied the problem correctly though. If the 10,000 is supposed to be 1,000, then the book would be correct.