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If `y=y(x)`satisfies the differential equation `8sqrt(x)(sqrt(9+sqrt(x)))dy=(sqrt(4+sqrt(9+sqrt(x))))^(-1)dx ,x >0a n dy(0)=sqrt(7,)`then `y(256)=`16 (b)80 (c) 3(d) 9A. 3B. 9C. 16D. 80 |
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Answer» Correct Answer - A We have, `dy=(dx)/(8sqrt(x)(sqrt(9+sqrt(x))(sqrt(4+sqrt(9+sqrt(x))))))` Let `4+sqrt(9+sqrt(x))=t` `rAr 1(2sqrt(9+sqrt(x))).1/(2sqrt(x))dx=dt` `rArr dy=(dt)/(2sqrt(t))` `rArr 2dy=1/sqrt(t)dt` `rArr 2y=2sqrt(t)+c` `rArr 2y=2sqrt(4+sqrt(9+sqrt(x)))` Given, `y(0) = sqrt(7) rArr c=0` `therefore y=sqrt(4+sqrt(9+sqrt(x)))` `therefore y(256)=3` |
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