Step 1: Find the order.
The given differential equation is
\[
y^2(y'')^2+3x(y')^{1/3}+x^2y^2=\sin x.
\]
The highest order derivative present is
\[
y''.
\]
Therefore, the order is
\[
a=2.
\]
Step 2: Remove the fractional power of derivative.
The term
\[
(y')^{1/3}
\]
contains a fractional power. To find the degree, the equation must be made free from fractional powers of derivatives.
Rearrange:
\[
3x(y')^{1/3}
=
\sin x-y^2(y'')^2-x^2y^2.
\]
Cubing both sides,
\[
27x^3y'
=
\left(\sin x-y^2(y'')^2-x^2y^2\right)^3.
\]
Step 3: Find the degree.
In the cubed equation, the highest order derivative is still
\[
y''.
\]
The highest power of \(y''\) comes from
\[
\left(y^2(y'')^2\right)^3.
\]
So the highest power of \(y''\) is
\[
2\times 3=6.
\]
Therefore, the degree is
\[
b=6.
\]
Step 4: Compare \(a\) and \(b\).
We have
\[
a=2
\]
and
\[
b=6.
\]
Thus,
\[
b=3a.
\]
Step 5: Final conclusion.
Therefore,
\[
\boxed{b=3a}
\]