Answer:
[tex]cos(x)=(+/-)0.44[/tex]
Step-by-step explanation:
we know that
[tex]sin^{2}(x)+cos^{2}(x)=1[/tex]
In this problem we have
[tex]sin(x)=0.9[/tex]
substitute and solve for cos(x)
[tex]0.9^{2}+cos^{2}(x)=1[/tex]
[tex]cos^{2}(x)=1-0.9^{2}[/tex]
[tex]cos^{2}(x)=0.19[/tex]
[tex]cos(x)=(+/-)0.44[/tex]
