Depends on what those subscripts mean. E.g., maybe this
y41 = -(x41^1.5 * cos(x41)^3) + 40;
y42 = x42 * sin(x42^2);
or this
y(41) = -(x(41)^1.5 * cos(x(41))^3) + 40;
y(42) = x(42) * sin(x(42)^2);
or this
y(4,1) = -(x(4,1)^1.5 * cos(x(4,1))^3) + 40;
y(4,2) = x(4,2) * sin(x(4,2)^2);
We need more context to answer your question.
