To other readers, the text of the question is as follows:
Ex 6.2.25 The two blades of a pair of scissors are fastened at the point A as shown in figure 6.2.9. Let a denote the distance from A to the tip of the blade (the point B ). Let β denote the angle at the tip of the blade that is formed by the line AB and the bottom edge of the blade, line BC, and let θ denote the angle between AB and the horizontal. Suppose that a piece of paper is cut in such a way that the center of the scissors at A is fixed, and the paper is also fixed. As the blades are closed (i.e., the angle θ in the diagram is decreased), the distance x between A and C increases, cutting the paper.
. . . . .
a. Express x in terms of a, θ, and β.
b. Express dx/dt in terms of a, θ, β, and dθ/dt.
c. Suppose that the distance a is 20 cm, and the angle β is 5 degrees. Further suppose that θ is decreasing at 50 deg/sec. At the instant when θ = 30 degrees, find the rate (in cm/sec) at which the paper is being cut.
To the original poster: When you say that you are stuck on dB/dt, does this mean that you've successfully completed Part (a)? Thank you!
