Log 2 (base) question

Question

Hi all,
How to use calculator (casio fx-50f) to calculate the following:

300 log2 (2.995) =474

**log2 is not log 2 is log base 2**

then

What is the answer if:

3400 log2 (4.162) = ?

Thanks!

Answer 1

首先，你要識得以下呢條公式：

logm n = loga n/loga m

知道左呢條公式之後， 只要代a做10、m做2、n做4.162，即係
log2 4.162 = log10 4.162/log10 2

即係按計數機上面既
[10]→[log]→[÷]→[2]→[log]
就會計到 log2 4.162 架啦！


希望幫倒你！^^

2006-12-21 23:14:48 補充：
打錯左少少，應該係按：[4]→[.]→[1]→[6]→[2]→[log]→[÷]→[2]→[log]→[=]

Answer 2

log2 (2.995) = log 2.995 / log 2
So you can press:
2, ., 9, 9, 5, LOG, /, 2, LOG, X, 3, 0, 0, =

Similarly, for 3400 log2 (4.162), press
4, ., 1, 6, 2, LOG, /, 2, LOG, X, 3, 4, 0, 0, =
Answer: 6994.741681.

Answer 3

Let y=2x
log2y=x
log10y=log102x =xlog102 ; x=log10y / log102
log2y=log10y / log102
3400 log24.162 = (3400)log104.162 / log102 = 6994.7