Tuesday, November 24, 2009

How to Calculate the Value of Any Number Whose Power is Negative ?

In annuity related problems , you have seen that , you have to calculate the value of number whose power is negative . For solving this , we can take the help of logarithm . We can take one example for telling you its
different steps

Suppose one number is = 1.05 with its power -8

Now we can solve it with the help of logarithm

suppose 





taking log both side

log x = -8  log  1.05  ( because power will come to front of log )

now we see the value of digit is one so we deduct one from one  ( 1-1 ) it is zero
calculate the value of log from lograthim table 10 in left colume and see value below 5th number of row

it is 0.0212

now multiply it with -8

log x = - 0.1696

now

write -1+1 in the front of -0.1696


log x = -1+1-0.1696

now -1 is seperated from -0.1696 , this value become positive after deducting from +1

or we can write


log x = -1.8304

now after point .8304 is positive and we can take antilog both side

log is cencelled with antilog

x = antilog -1.8304


now add +1 in -1 and result will be zero , now only leave zero number for writing point

after finding the value of .83 in 0 and in 4

6767

now we leave zero and write point

x = 0.6767