Chemegate

GATE 2024 Chemical Engineering, Q52 · Mathematics

The correct answer is 4 to 4.08.

Question

Consider the ordinary differential equation x2(d2y/dx2)x²(d²y/dx²) − x(dy/dx) 3y = 0, with the boundary conditions y(x=1) = 2 and y(x=2) = 17/2. The solution y(x) at x = 3/2, rounded off to 2 decimal places, is ___________

Official answer: 4 to 4.08

Why

GATE 2024 official key: 4.00 to 4.08. This Cauchy-Euler equation has solutions y=xmy=x^{m} with m22m3=0m²−2m−3=0 \Rightarrow m=3,−1, so y=C1x3+C2/x.y=C1x³+C2/x. BCs give C1=C2=1, so y(x)=x3+1/x.y(x)=x³+1/x. At x=1.5: y=3.375+0.6674.04.y=3.375+0.667\approx 4.04.

Explanation cross-checked for consistency. Final answer matches the official IIT answer key.