**Section 1.2, #57.** The problem in the solutions guide is from a different problem that appeared in the previous edition of the textbook. Please omit the problem.
**Section 1.4, problem 95.** The solution in the solutions guide does not correspond with the problem in the textbook. To solve the problem, replace t with -0.7 in the formula and evaluate the expression on the right side to find the current to be I=0.794 amperes. [Be sure the calculator is in radian mode].

**Section 1.4, problem 96.** The solution in the solutions guide does not correspond with the problem in the textbook. To solve the problem... In the right triangle illustration, notice that the length of the opposite side is given (6 miles) and the hypotenuse is the distance we want to calculate. The trig ratio involving the opposite side and the hypotenuse is sine.

sin theta=opposite/hypotenuse

sin theta=6/d

Since all of the questions ask for the value of d, the distance to the airplane, it might be helpful to solve for d...

d=6/sin theta

Plug in the given values of theta to find the distances.

(a) When theta=30... [Make sure the calculator is in degree mode].

d=6/sin 30 degrees

d=12 miles

**Section 1.6, problem 9.** In the solutions guide, the graph is incorrect. The period should be pi/3 rather than pi.