If Dave is standing next to a silo of cross-sectional radius r = 9 feet at the indicated position, his vision will be partially obstructed. Find the portion of the y-axis that Dave cannot see. (Hint: Let a be the x-coordinate of the point where line of sight #1 is tangent to the silo; compute the slope of the line using two points (the tangent point and (12, 0)). On the other hand, compute the slope of line of sight #1 by noting it is perpendicular to a radial line through the tangency point. Set these two calculations of the slope equal and solve for a. Enter your answer using interval notation. Round your answer to three decimal places.) Really confused on this question I dont even know where to start.
You don't need any caluculs to do this problem. Draw the picture.... Unfortunately, the description here doesn't explain everything to solve the problem (where is the center of the silo in x, y space?) I am going to take a guess that it is at the origin. draw a line from Dave to the center of the silo. Draw a line from Dave to his line of sight, and continue it until it hits the y axis.... Draw the radius of the silo along the path from the center to the tangent point. The angle of obscured veiw is then t = acos (9/12) cos t = 3/4 sin t = (1-(3/4)^2) = sqrt (5)/ 4 tan t = sqrt 5 / 3 and the the section of the y axis that is obscured is [-12 tan t, 12 tan t] = [-4 sqrt 5 , 4 sqrt 5 ]
