Array indices must be positive integers or logical values.

function [out] = slope(t,G1,G2,G3,G4)
k1=10;k2=20;m1=2;m2=4;

out(1)=(-k1*G2+k2(G4-G2))/m1;
out(2)=G1;
out(3)=-k2(G4-G2)/m2;
out(4)=G3;
end

when I use this function liks slope(0,1,0,-1,0)

show me thia Array indices must be positive integers or logical values.

Error in slope (line 4)

out(1)=(-k1*G2+k2(G4-G2))/m1;

why? how I can fix it.

Answer 1

[the cyclist]

You need to explicitly put in the multiplication sign:

out(1)=(-k1*G2+k2*(G4-G2))/m1;

and similarly in the assignment to out(3):

out(3)=-k2*(G4-G2)/m2;