The Wave height in an open sea is a function of wind speed and the length of the time is represented as .

(a)

is rate of change of wave height as wind speed varies, with time fixed.

  is rate of change of wave height as time varies, with wind speed fixed.

(b)

Estimate .

.

Assume values depending on Table.

Let .

Observe the table: and .

For , .

Let .

Observe the table: and .

For , .

Therefore, the average of the two values is .

.

For a wind speed of and constant length of time of , the wave height rises by unit for each rise in the wind speed.

Estimate .

.

Assume values depending on Table.

Let .

Observe the table: and .

For , .

Let .

Observe the table: and .

For , .

Therefore, the average of the two values is .

.

For a constant wind speed of and length of time of , the wave height rises by for each and every hour increase in length of the time.

(c)

Observe the table:

As time increases, the change in height decreases.

Therefore, .

(a)

is rate of change of wave height as wind speed varies, with time fixed.

  is rate of change of wave height as time varies, with wind speed fixed.

(b)

.

For a wind speed of and constant length of time of , the wave height rises by unit for each rise in the wind speed.

.

For a constant wind speed of and length of time of , the wave height rises by for each and every hour increase in length of the time.

(c) .