[croan216]

Trying to get the value of "t"

1.015^t=4

[croan216]

I know that T equals 93 but I can't remember the method to get there.

Cheers

[KISS]

93 to 0 decimal places.

Take the log of both sides. Is that enough of a hint. Yea, I checked my answer.

[morgaine300]

This is how I remember to do this. Someone will probably have a hissy fit cause there's certainly nothing "proper" about it -- it's just something that works so I can remember it.

If that were 1.015t = 4, without the exponent, you would divide both sides by 1.015 to solve for the t. So the left would cancel out to just t. And the right would be 4 divided by 1.015.

However, it's not 1.015t, it's 1.015^t so you see that's not something you can really do. What it does do is remind you to divide the 4 by 1.015, except you're going to divide the log of 4 by the log of 1.015. I have to do this to remember which to divide by which.

[KISS]

Taking the log of both sides it becomes t * log(1.015)=log(4) which is easy to solve for t.