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Let a solution y = y(x) of the differential equation `xsqrt(x^2-1) dy - y sqrt(y^2-1) dx=0`, satisfy `y(2)= 2/sqrt 3`A. (a) Statement I is true, Statement II is also true, Statement II is the correct explanation of Statement I.B. (b) Statement I is true, Statement II is also true, Statement II is not the correct explanation of Statement I.C. (c) Statement I is true, Statement II is false.D. (d) Statement I is false, Statement II is true. |
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Answer» Correct Answer - (c) Given , `dy/dx=(ysqrt(y^(2)-1))/(xsqrt(x^(2)-1))` `int dy/ (ysqrt(y^(2)-1))=intdx/(xsqrt(x^(2)-1))` `rArr sec^(-1) y=sec^(-1) x+c` `At x=2, y = 2/sqrt(3), pi/6=pi/3+c` `rArr c=- pi/6` Now, `y = sec (sec^(-1)x-pi/6)` `=cos [cos^(-1)frac {1}{x}-cos^(-1) frac{sqrt(3)}{2}]` `= cos [ cos ^(-1) (sqrt(3)/(2x)+sqrt(1-1/x^(2))sqrt(1-3/4)]` `y=sqrt(3)/(2x)+1/2 sqrt(1-1/x^(2))` |
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