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Question: Answered & Verified by Expert
If the solution curve, of the differential equation dydx=x+y-2x-y passing through the point (2,1) is tan-1y-1x-1-1βlogeα+y-1x-12=logex-1, then 5β+α is equal to
MathematicsDifferential EquationsJEE MainJEE Main 2024 (27 Jan Shift 2)
Solution:
1912 Upvotes Verified Answer
The correct answer is: 11

Given: dydx=x+y-2x-y

Now, finding the intersection point of x+y-2=0 and x-y=0.

x+x-2=0, x=y

x=1, y=1

x,y1,1

Let, x=X+1, y=Y+1

dYdX=X+YX-Y

Putting, Y=tX

dYdX=t+XdtdX

1+t1-t=t+XdtdX

1+t-t+t21-t=XdtdX

1XdX=1-t1+t2dt

1XdX=1-t1+t2dt

logX=tan-1t-12log1+t2+C

logx-1=tan-1y-1x-1-12log1+y-1x-12+C

It is given that the solution curve passes through 2,1.

log2-1=tan-11-12-1-12log1+1-12-12+C

0=tan-10-12log1+C

C=0

α=1, β=2

5β+α=11.

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