Tuesday 11 February 2014

LOGARITHMS B24

Evaluate the following giving your answer in standard form.

78.7 x 10-9
   5 x 10-20

Solution

78.7 x 10-9
       5 x 10-20

78.7  x   10-9
       5         10-20

=  15.74 x 10-9 –(-20)

=  15.74 x 10-9 + 20    

=  15.74 x 1011      then we change 15.74 into standard form as well

= 1.574 x 101 x 1011   when we have exponents with same base, we add the
                                    Powers.

= 1.574 x 101+11

= 1.574 x 1012

Hence   78.7 x 10-9   = 1.574 x 1012
                 5 x 10-20


TRY THIS..............

Evaluate the following giving your answer in standard form.

456.9 x 10-8
   5 x 10-30


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