Q:  Can you estimate how long it will take for
    the rotation rate of pulsar PSR 0833-45 to
    reach half its present value?


       Current frequency    f1  =  11.205 cycles per second
       
                              11.209 cycles/sec - 11.203 cycles/sec 
       rate of slowdown   =   --------------------------------------
                                    5000 days - 1000 days


                          =   1.5 x 10^(-6)  cycles/sec  per day



       In order to go from current rate to half current rate, 
       must decrease to

             1/2 f1  =  5.6  cycles per second

       which means that it will change from 11.2 to 5.6 cycles per sec,
       a change of 5.6 cycles per second.  That will take
       
                              change of 5.6 cycles/sec
                    ----------------------------------------------
                     change rate  1.5 x 10^(-6) cycles/sec per day



                 =    about   3,700,000  days

                 =    about      10,000  years