1. CS 121 – Quiz 3 Question 5

2. This question is just a different form of question four you solved at quiz 2. a) We need to use law of cosines to solve the question. b) Law of Cosines: a^2 = b^2 + c^2 – 2*b*c*cos(alpha) In our case, we will take b = D, c = H and alpha = some value related to a given in Degrees.

3. c) First assign parameters to given values. d) Then we need to calculate what alpha is. It is going to be different for left and right sides of the tower. – Since tower is perpendicular to the earth center, alpha is going to be either 90-a or 90+a Degrees for sides of the tower. – Keep in mind that Maple uses Radians for trigonometric functions like sin and cos. So we will need to convert Degrees to Radians. – We should assign that calculated value to alpha. e) Then we have Law of Cosines expression with one unknown.

4. f) Solve equation for the unknown. You will have a positive and a negative root. Definitely negative root is meaningless for this case. g) You will need to change the angle to calculate length of left and right sides separately. h) For the second version of the problem, you will just change the parameters, recalculate everything and find cost of wires.