Question
Mathematics Question on Differential equations
Let αx =exp(x βyγ) be the solution of the differential equation 2 x 2 ydy −(1− xy 2) dx = 0, x >0 , y(2)=loge2. Then α +β − γ equals :
A
0
B
−1
C
1
D
3
Answer
1
Explanation
Solution
αx=exβ⋅y7
2x2ydxdy=1−x⋅y2y2=t
x2dxdt=1−xt
dxdt+xt=x21 I.F. =e(nx=x
t(x)=∫x21⋅xdx
y2⋅x=ℓnx+C
∴2⋅ln2=ℓn2+C
∴C=ln2
Hence, xy2=ℓn2x
∴2x=ex⋅y2
Hence α=2,β=1,γ=2