Step 1 :Set the height function equal to 11: \(11 = 17.6 - 15.5 \cos\left(\frac{2\pi}{5}t\right)\)
Step 2 :Rearrange the equation to isolate the cosine function: \(15.5 \cos\left(\frac{2\pi}{5}t\right) = 17.6 - 11\)
Step 3 :Simplify the right side of the equation: \(15.5 \cos\left(\frac{2\pi}{5}t\right) = 6.6\)
Step 4 :Divide both sides by 15.5 to solve for the cosine function: \(\cos\left(\frac{2\pi}{5}t\right) = \frac{6.6}{15.5}\)
Step 5 :Simplify the right side of the equation: \(\cos\left(\frac{2\pi}{5}t\right) = 0.425806\)
Step 6 :Use the inverse cosine function to solve for \(\frac{2\pi}{5}t\): \(\frac{2\pi}{5}t = \arccos(0.425806)\)
Step 7 :Solve for t: \(t = \frac{5}{2\pi} \arccos(0.425806)\)
Step 8 :Calculate the value of t: \(t = \frac{5}{2\pi} * 1.094\)
Step 9 :Simplify to find the first time when the person is 11 meters above the ground: \(t = 0.87\) minutes
Step 10 :Find the second time within the first 5 minutes when the person is 11 meters above the ground: \(t = 5 - 0.87\)
Step 11 :Simplify to find the second time when the person is 11 meters above the ground: \(t = 4.13\) minutes
Step 12 :The person will be 11 meters above the ground at approximately \(\boxed{0.87}\) minutes and \(\boxed{4.13}\) minutes