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Differential Equations

Question
CBSEENMA12033167

Solve:
straight x dy over dx plus 2 straight y space equals space straight x squared log space straight x

Solution
The given differential equation is
           straight x dy over dx plus 2 straight y space equals space straight x squared space logx
or      dy over dx plus 2 over straight x straight y space equals space straight x space logx
Comparing it with dy over dx plus Py space equals space straight Q comma space space we space get comma space space straight P space equals space 2 over straight x comma space space straight Q space equals space straight x space log space straight x
therefore space space space integral straight P space dx space equals space 2 space integral 1 over straight x dx space equals space 2 space log space straight x. space straight e to the power of integral straight P space dx end exponent space equals space straight e to the power of 2 space log space straight x end exponent space equals space straight e to the power of log space straight x squared end exponent space equals space straight x squared
Solution of given differential equation is
                    straight y space straight e to the power of integral straight P space dx end exponent space equals space integral straight Q space straight e to the power of integral straight P space dx end exponent dx plus straight c
or             straight y. straight x squared space equals space integral straight x space log space straight x. space straight x squared space dx plus straight c
or space space straight x squared. straight y space equals space integral left parenthesis log space straight x right parenthesis. space straight x cubed space dx space plus straight c
or space space straight x squared straight y space equals space left parenthesis log space straight x right parenthesis. space straight x to the power of 4 over 4 minus integral 1 over straight x. straight x to the power of 4 over 4 dx plus straight c
or space space space straight x squared straight y space equals space straight x to the power of 4 over 4 log space straight x space minus space 1 fourth integral straight x cubed space dx plus straight c
or space space space straight x squared straight y space equals space straight x to the power of 4 over 4 log space straight x minus space 1 fourth. space straight x to the power of 4 over 4 plus straight c
or space space space straight y space equals straight x squared over 4 log space straight x space minus space 1 over 16 straight x squared plus straight c space straight x to the power of negative 2 end exponent space is space the space required space solution. space

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