4. The cooling curve below represents the uniform cooling of a substance, starting at a temperature above its boiling point.
Cooling Curve
5
Temperature (°C)
1
1
1
!
1
i
.
1
1
1
1
0
1
2
3
4
5
6
7
8
9
10
11
Time (min)
During which time interval does the substance exist as both a liquid and a gas?
(1) min 2 to min 4
(2) min 2 to min 6
(3) min 5 to min 7
(4) min 7 to min 9
6

The number of medals awarded to the track team during the season.

Following are the  advantages of the parametric equations: 1) they can be used to graph curves that are not functions, like the unit circle.2) the parameter can be used to represent the quantity that is  useful to  provide us with better information about the graph.3)  it is useful to convert between rectangular equations and parametric equations.with specific reference to chemistry,  parametric equations are employ for solving hydrogen and hydrogen-like ions, quantum mechanically. herein, cartesian coordinates are converted in spherical polar coordinates. the solution obtained, when plotted on spherical polar graph paper, provides visualization of atomic orbital such as s,p,d and f.