Answer:
[tex]-i[/tex]
Step-by-step explanation:
We use the fact that [tex]i^{2} =-1[/tex] to rewrite the expression and simplify :
[tex]i^{43} =i-^{42} * i\\=(i^{2} )^{21} *i\\=(-1)^{21} *i\\\\=-i[/tex]