Suppose h(x)= 1/sqrtx for x>0. Does h have an inverse? If so, find h^{-1}(4). If not, enter "undef".
h (x) = 1 / √x
y = 1 / √x square both sides
y^2 = 1/x
x = 1/y^2 swap x and y and for y wriite h-1(x)
y = h-1(x) = 1 / x^2
And h-1(4) = 1 / 4^2 = 1 / 16
+646 
