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Relations And Functions

Question
CBSEENMA12035790

Solve the differential equation straight x dy over dx space plus straight y space equals space straight x space cos space straight x space plus space sin space straight x comma space given space that space straight y space equals space 1 space when space straight x space equals space straight x over 2

Solution

The given differential equation is
straight x dy over dx space plus straight y space equals space straight x space cos space straight x space plus space sin space straight x
rightwards double arrow space dy over dx space plus straight y over straight x space equals fraction numerator space straight x space cos space straight x space plus space sin space straight x over denominator straight x end fraction
Let space comma space space straight U space equals space 1 over straight x comma space space straight V space space equals space fraction numerator straight x space cos space straight x space plus space sin space straight x over denominator straight x end fraction
Now comma space straight I. straight F space equals space straight e integral Udx space equals space space equals space straight e integral 1 over straight x dx space equals space straight e to the power of log space straight x end exponent space equals space straight x
Now comma
ye integral Udx space equals space integral Ve to the power of integral Udx end exponent dx
rightwards double arrow space straight y. straight x space equals space integral fraction numerator straight x space cos space straight x space plus space sin space straight x over denominator straight x end fraction. space straight x space dx
rightwards double arrow space xy space equals space integral left parenthesis straight x space cos space straight x space plus space sin space straight x space right parenthesis space dx
rightwards double arrow space xy space space equals space integral space straight x space cos space straight x space dx space space plus space integral space sin space straight x space dx
rightwards double arrow space xy space equals space space straight x space sin space straight x space minus space integral space sin space straight x space dx space plus space integral sin space straight x space dx space plus space straight C
rightwards double arrow space xy space equals space straight x space sin space straight x space plus straight C
rightwards double arrow space straight y space equals space sin space straight x space space plus straight C over straight x
Given space space colon space straight x space equals space straight pi over 2 space comma space space space straight y space equals 1
rightwards double arrow space 1 space equals space sin space straight pi over 2 space space plus fraction numerator straight C over denominator straight pi divided by 2 end fraction
rightwards double arrow space 1 space equals space 1 space plus space fraction numerator straight C over denominator straight pi divided by 2 end fraction
rightwards double arrow space straight C thin space equals space 0