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Mathematics 21 Online
OpenStudy (anonymous):

solve diff eq sinxcosx*dy\dx=y+sinx

OpenStudy (anonymous):

take dx to the othr side

OpenStudy (anonymous):

You can split the eq

OpenStudy (anonymous):

and then split

OpenStudy (anonymous):

dy\dx = y+sinx \ sin x cos x .... sinxcosx = it would look like this.. dy\dx = y + sin x \ sinxcosx =0 .. rewrite it to.. dy\dy - y\1\2 sin2x = sinx \sinxcosx dy\dy - y\1\2 sin2x = 1\cosx .. hope i did nt to any wrongs..

OpenStudy (anonymous):

hmmm...yeah its fine till here...

OpenStudy (anonymous):

i got the same :)

OpenStudy (anonymous):

go on ...type

OpenStudy (anonymous):

Then, you need to find the Integration factor.. and U\[U \times Y \int\limits_{}^{} U \times 1\div cosx... Their .. U = e ^{\int\limits_{}^{} 1\div (1\div 2 \times \sin (2x))}\]

OpenStudy (anonymous):

sry i forgott i Minus before U=e∫-1÷(1÷2×sin(2x)

OpenStudy (anonymous):

hmm....then..

OpenStudy (anonymous):

hey i think the person who asked the question is not here

OpenStudy (anonymous):

aha..

OpenStudy (anonymous):

Have u done the this?

OpenStudy (anonymous):

that makes it \[e ^{\int\limits_{}^{} 2/sin2x}\]

OpenStudy (anonymous):

yepp

OpenStudy (anonymous):

And that Integral, i am not sure of..

OpenStudy (anonymous):

you can take, u =sin 2x and solve

OpenStudy (anonymous):

aha, so u mean that e∫2/sin2x = sin2x

OpenStudy (anonymous):

no, not that 'U', lets take.. say p=sin2x, so that , int(1/p) = log p = log (sin 2x) ...got it?

OpenStudy (anonymous):

noe it gives e^ (log (sin 2x))

OpenStudy (anonymous):

*now

OpenStudy (anonymous):

:P

OpenStudy (anonymous):

ln (1\p)

OpenStudy (anonymous):

why ln (1/p) ?

OpenStudy (anonymous):

Okey, i see..

OpenStudy (anonymous):

\[\int\limits_{}^{} 1\div p =\ln p\]

OpenStudy (anonymous):

yupp

OpenStudy (anonymous):

what about the inner derivata? 2x

OpenStudy (anonymous):

1\2 must be 1\2lnp

OpenStudy (anonymous):

that 2 in the denominator o f '1/2' goes to the numerator as '2'

OpenStudy (anonymous):

Found it. ∫ 1/sin(2x) dx = ∫ csc(2x) dx. Let u = 2x <==> du = 2 dx. Then, the integral becomes: 1/2 ∫ csc(u) du = -ln|cot(u) + csc(u)|/2+ C = -ln|cot(2x) + csc(2x)|/2 + C. <== ANSWER

OpenStudy (anonymous):

good going :)

OpenStudy (anonymous):

finally, got the answer huh:)

OpenStudy (anonymous):

haha.. yeah.. long time ago, with math..

OpenStudy (anonymous):

Need to refresh my memory!

OpenStudy (anonymous):

ha ha ..anyways you found it

OpenStudy (anonymous):

@nabaz&thinker thnxs for the help buddies i am getting the same ! but the ans is given to b \[y cotx=c+lntan \left( x/2 \right)\] is it the same?

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