Maths

[Craig100]

Hey,

Well this question has got me stuck,
if i have a number such as 16777216 which is 2 ^ 24, but, how can i, without trial and error, get that it is 2 ^ 24. in this case i know the answer is 2^24 but sometimes it may not be that simple. this is a question in computing which asks for me to figure out the minimum width of an address bus in a system with 64MB of ram organsied in 32bit words.

What i done so far is change 64mb into bits, and divide it by 32 , which gives the answer above, and is 2^24. but without guessing that it is 2^24 and checking it, is there another way i can get this?

[doctorgonzo]

Are you trying to figure out X in this equation: 2^X=some number?

If so, then it is simple: diving the natural logarithm (usually LN on calculators) of the "some number" by the natural log of 2.

For example, (ln 16777216)/(ln 2) = 16.6355/.6931 = 24, so 16777216 = 2^24.

[Craig100]

Thats exactlly what i want to do , i get what you mean, i have tried it out successfully, thankyou.

Regards