How do you use a calculator to evaluate the expression #log5# to four decimal places?

1 Answer
Jan 31, 2017

Answer:

#0.698970004 rarr 0.6990#

Explanation:

As there is no base shown, it is assumed that the base is 10.

Calculators have a key: LOG

If you have a D.A.L. calculator the key presses are as follows:

LOG 5 =

The display will be #0.698970004#

The older calculators require the 5 to be entered first and then LOG.
The answer is displayed immediately without =being pressed.

5 LOG

The display will be #0.698970004#

To round to 4 decimal places, consider the value in the fifth place.

#0.6989color(blue)(7)0004#

#7# is more than 5, so the digit to the left will round up.
The #9# becomes 10, meaning the #8# will become #9#.
#(89 rarr 90)#

#0.698color(red)(9)70004# rounds to

#0.6990#

The final #0# must be shown otherwise there will not be 4 places.