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**1.A kite 40 m above the ground moves horizontally at the rate of 3 m/s. At what rate is the angle between the string and the horizontal decreasing when 80 m of string has been let out. Answer is 0.02 m/s**

**2. What I did was:**

-Drew a triangle as prescribed above

-I found the unknown length of the ground at that instaneous time.

-I found the derivative of the vertical height.

-Then I took derivative of sin theta which gave:

cos theta (d theta/t) = ry'-yr'(becomes 0 since the string is 80 m all the time) all divided by r^2

Then I divide by cos theta to get the derivitive the angle.

-Drew a triangle as prescribed above

-I found the unknown length of the ground at that instaneous time.

-I found the derivative of the vertical height.

-Then I took derivative of sin theta which gave:

cos theta (d theta/t) = ry'-yr'(becomes 0 since the string is 80 m all the time) all divided by r^2

Then I divide by cos theta to get the derivitive the angle.

Thanks very much