...In general, dx 1 , , b " ^"* . The first expression is real when 6 is positive ; the second when b is negative. Both a and 6 cannot be negative at the same time. Hence, we have • <fc 1 . , 6 1 II. f - rr= — r sm."i^ — ' J —^ va < 1 1 = — TT sec." 1 a 1 . , = _ eosec-...