How do you find the vertex and intercepts for #y^2=1/3x#?

2 Answers
Dec 23, 2015

#(0,0)# is only intercept.
#"vertex"=(oo,oo)#

Explanation:

For #y=0#,
#color(white)xxx=0#

Therefore #(0,0)# is only intercept.

#y=sqrt(1/3x)#
Therefore #y# is positive for #AA x inRR^+#.

#y'# is also positive for #AA x inRR^+#:
#y'=1/(2sqrt3sqrtx)#

Therefore there is no real vertex:
#"vertex"=(oo,oo)#

graph{sqrt(1/3x) [-10, 10, -5, 5]}

Dec 23, 2015

The vertex and intercepts are all at #(0, 0)#

Explanation:

If #x = 0# then #y^2 = 0#, so #y = 0#.

If #y = 0# then #1/3 x = 0#, so #x = 0#.

So the only #x# and #y# intercepts are at #(0, 0)#

#y^2 >= 0# for any Real value of #y#, hence the minimum possible value of #x# is #0#. So the vertex of the parabola is at #(0, 0)#.

Both positive and negative values are possible for #y#.

#y# is not a function of #x#, but #x# is a function of #y#...

graph{y^2=x/3 [-5.22, 12.56, -4.484, 4.405]}