let assume

we know from defination of inverse function
tan y = opposite / adjacent
here opposite is 5 and adjacent is 1
tan y = 5/1
lets calculate hypotenus using pythagoras theorem
hypotenuse = root ( 5^2 + 1^2)= root (25+1) = root (26)
now we know
sin y = opposite / hypotenus
so

hope it helps you