use vertex forom
y=a(x-h)²+k
(h,k) is the vertex
a is some constant
ok, so we se the vertex is (0,1)
h=0, k=1
y=a(x-0)²+1
y=ax²+1
we also see it passes through (1,3)
subsitute to find the value of a
x=1 and y=3
3=a(1)²+1
3=1a+1
3=a+1
2=a
so the equation is
y=2x²+1
