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Differential Equations

Question
CBSEENMA12033188

Solve:
dy over dx plus 2 straight y space equals space sin space 3 straight x

Solution
The given differential equation is
              dy over dx plus 2 straight y space equals sin space 3 straight x
Comparing it with dy over dx plus Py space equals space straight Q comma space we space get comma
                     P = 2,    Q = sin 3x
     integral straight P space dx space equals space integral 2 space dx space equals space 2 straight x
            straight I. straight F. space equals space straight e to the power of integral Pdx end exponent space equals space straight e to the power of 2 straight x end exponent
therefore space space space solution space of space differential space equation space 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 space space space space space or space space space straight y space straight e to the power of 2 straight x end exponent space equals space integral straight e to the power of 2 straight x end exponent space sin space 3 straight x space dx space plus straight c
therefore space space space space ye to the power of 2 straight x end exponent space equals space fraction numerator 1 over denominator square root of 4 plus 9 end root end fraction space straight e to the power of 2 straight x end exponent space sin space open parentheses 3 straight x minus tan to the power of negative 1 end exponent 3 over 2 close parentheses space plus straight c
                                              open square brackets because space space space integral straight e to the power of ax space sin space bx space dx space equals space fraction numerator 1 over denominator square root of straight a squared plus straight b squared end root end fraction straight e to the power of ax space sin open parentheses bx minus tan to the power of negative 1 end exponent straight b over straight a close parentheses close square brackets
or               straight y equals space fraction numerator 1 over denominator square root of 13 end fraction sin space open parentheses 3 straight x minus tan to the power of negative 1 end exponent 3 over 2 close parentheses plus space ce to the power of negative 2 straight x end exponent
which is required solution.

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