is in quadrant I, so
.
is in quadrant II, so
.
Recall that for any angle
,

Then with the conditions determined above, we get

and

Now recall the compound angle formulas:




as well as the definition of tangent:

Then
1. 
2. 
3. 
4. 
5. 
6. 
7. A bit more work required here. Recall the half-angle identities:



Because
is in quadrant II, we know that
is in quadrant I. Specifically, we know
, so
. In this quadrant, we have
, so

8. 
i would think that the depression would be from the boat as its about to off a cliff but more at a 45 to 80 degree angel as it falls of the cliff

Converting to spherical coordinates, we have

On the other hand, we can parameterize the boundary of

by

with

and

. Now, consider the surface element



So we have the surface integral - which the divergence theorem says the above triple integral is equal to -


as required.
Answer: 2 inch dimension will give smallest increase.
Step-by-step explanation:
Length = 3 in
width = 2 in
height = 6 in
Extra cardboard means to find surface area
on doubling the length
length = 6 In
width = 2 In
Height = 6In
Surface area for the above dimensions = 2 [ 6x2+2x6+6x6] = 120 sq in
On doubling the width
length = 3 in
width = 4 in
Height = 6 inch
Surface area for the above dimensions= 2 [ 3x4+4x6+6x3] = 2[54] = 108 sq inches
On doubling height
Length =3 in
width = 2 in
Height = 12 in
Surface area for above dimensions = 2 [ 3x2+2x12+12x3] = 2[6+24+36] = 132 sq inch
On doubling width surface area is minimum.