First of all, observe that the graphed function is [tex]y=\sin(x)[/tex].
Now, if we want to shift the graph 4 units up, it means that we want each point on the graph enlarge its y coordinate by 4: we no longer want to associate
[tex]x\mapsto y[/tex]
but
[tex]x\mapsto y+4[/tex]
And since [tex]y=f(x)[/tex], we want to map
[tex]x\mapsto f(x)+4[/tex]
And in our case, [tex]f(x)=\sin(x)[/tex], so the answer is
[tex]\sin(x)+4[/tex]
