The function hours.

Find the number of hours of daylight in Houston,Texas North latitude of Texas ( North lattitude).

Convert latitude from seconds to normal degree representation angle.

.

(a)

Summer solstice ().

Find .

Substitute the values and in above function.

Convert angle from degrees to radians.

.

The function hours.

Substitute the value in above function.

.

(b)

Vernal equinox ().

Calculate .

Substitute the values and in above equation.

Convert angle from degrees to radians.

The function hours.

Substitute the value  in above function.

.

(c)

July 4( ).

Calculate

Substitute and

Convert angle from degrees to radians

The function hours.

Substitute in day above function. \ \

.

(a) .

(b) .

(c) .