<u>Answer:</u>
- The first four terms are <u>4</u><u>,</u><u>8</u><u>,</u><u>1</u><u>2</u><u>,</u><u>1</u><u>6</u>
<u>Step-by-Step </u><u>Explanation</u><u>:</u>
The given relation between the nth term and it's previous term is given by:

GiveN:
Now finding the other three terms of the AP with the given relation.

Putting a1 = 4,

Now, Third term:

Putting a2 = 8,

Now, Fourth term:

Putting a3 = 12,

Hence, The first four terms of the AP is 4, 8, 12 & 16.
Start at (0, 135) and work your way down 15 and over one each time. Your next point would be (1, 120)
To determine the number of cubes he needs to fill the box (this is assuming the cubes are 1 in cubes, he would need to calculate the volume of the box. To find the volume he would multiply the length by the width by the height. This would be 5 in x 6 in x 7 in. The volume is 210 cubic inches, so he could fill it with 210 one inch cubes.
Pi/3 is equivalent to 60 degrees, as 2pi is equal to 360 degrees. cos(60) in a triangle yields 1/2, and sin(60) yields (3^(1/2))/2. Thus, -pi/3, or -60 degrees would be a fourth quadrant point on the unit circle and these values would be negative as well, at cos(-pi/3)=-1/2 and sin(-pi/3)=-(3^(1/2))/2