Question

can someone please help me

Answer 1

Step-by-step explanation:

A. First, convert 30 minutes to a hour.

$\frac{30 \: mins}{1} \times \frac{1 \: hour}{60 \: mins} = 0.5 \: hours$

$4 + 0.5 = 4.5 \: hours$

Now, we can subsitue.

Part A: 1.

$d(t) = 6 + 5.5 \cos( \frac{\pi}{6}(4.5) )$

$d(t) = 6 + 5.5 \cos( \frac{3\pi}{4} )$

Part B:

$\cos( \frac{3\pi}{4} ) = - \frac{ \sqrt{2} }{2}$

so

$6 + 5.5( - \frac{ \sqrt{2} }{2} )$

which is approximately

2.11. feet.

Part C: The depth of the water is approximately 2.11 feet in 4.5 hours, or 4 hours and 30 minuties.