-->

Differential Equations

Question
CBSEENMA12033137

Solve:
straight x dy over dx minus straight y plus straight x space tan straight y over straight x equals 0

Solution
The given differential equation is
                straight x dy over dx minus straight y plus straight x space tan straight y over straight x space equals space 0
or                                    straight x dy over dx space equals space straight y minus straight x space tan straight y over straight x
or                                   dy over dx space equals space straight y over straight x minus tan straight y over straight x
Put y = v x so that      dy over dx space equals straight v plus straight x dv over dx
therefore space space space space space space space space straight v plus straight x dv over dx space equals straight v minus tan space straight v
therefore space space space space space straight x dv over dx space equals space minus tan space straight v
or space space space space space space space space space space space space space space fraction numerator 1 over denominator tan space straight v end fraction dv space equals space minus 1 over straight x dx
therefore space space space space space space space space space space integral fraction numerator 1 over denominator tan space straight v end fraction dv space equals space minus integral 1 over straight x dx
therefore space space space space space space space space space space log space open vertical bar sin space straight v close vertical bar space equals space minus log space open vertical bar straight x close vertical bar space plus space log space open vertical bar straight c close vertical bar
or space space space space space space space space space space space space log space open vertical bar straight x space space sinv close vertical bar space equals space log space open vertical bar straight c close vertical bar
therefore space space space space space space space space space space space space space straight x space space sin space straight v space equals space straight c
or space space space space space space space space space space space space space space space space straight x space sin space straight y over straight x space equals space straight c space is space the space required space solution. space

Some More Questions From Differential Equations Chapter