Find a function f such that f(1) = 0 and f'(x) = 2^(x) / x
Follow Math Help Forum on Facebook and Google+
Originally Posted by TsAmE Find a function f such that f(1) = 0 and f'(x) = 2^(x) / x $\displaystyle f(x) = \int_1^x \frac{2^t}{t} \, dt$.
Originally Posted by mr fantastic $\displaystyle f(x) = \int_1^x \frac{2^t}{t} \, dt$. I love it when it's simple ...
Arent you suppose to find the anti-derivative of f'(x) = 2^(x) / x?
Originally Posted by TsAmE Arent you suppose to find the anti-derivative of f'(x) = 2^(x) / x? In that case, good luck ....
Originally Posted by mr fantastic In that case, good luck .... I am not sure of the method you used, thats why I asked, as I thought that the only of finding it was by using an anti-derivative
Mr F did not use any method .. He get the answer by using the FTC .. The problem here is that $\displaystyle \int \frac{2^x}{x} \, dx$ is unelementary integral .. What ever you do, you can not evaluate it in terms of elementary functions ..
View Tag Cloud