Sine Cosine Game
by Marsha Hurwitz, Houston, Texas, in the Mathematics Teacher
After I introduce my students to the sine and cosine functions, I
begin a class period with the following game that has proved quite
successful. First I divide the class into pairs and distribute single
sheets of paper to each pair. On this sheet are two columns. The
left-hand column contains expressions involving either the sine or
cosine function. In the right-hand column are actual decimal
approximations of the expressions in the left-hand column,
but in a random order. The values are chosen such that only one of the
five decimal values is plausible for each function.
At the signal from me, each pair has three minutes to match each
expression in the left-hand column with its proper decimal
representation in the right-hand column. Calculators are not
permitted. Any pair is a winner if it obtains all five correct matchings.
After I have introduced all six trigonometric functions, I play the
same game but mix secant with cosine or cosecant with sine expressions
in the left-hand column. The game can be made even more challenging by
using more trigonometric expressions in this column. However, ambiguities
are more likely to occur, so care must be taken. Students have responded very
well to this exercise. It especially reinforces those skills involving
deductive reasoning, graph interpretation, and approximation. Finally,
students are given an opportunity to learn from, and work with, each other.
Precalculus Names: __________
__________
Matching #1
_______ cos 35 A. -0.9961
_______ cos 98 B. 0.8192
_______ cos 4 C. 0.0349
_______ cos 175 D. -0.1391
_______ cos 272 E. 0.9976
Precalculus Names: __________
__________
Matching #2
_______ sin 224 A. 0.1908
_______ sin 52 B. 0.7888
_______ sin 290 C. -0.0871
_______ sin 355 D. -0.6946
_______ sin 11 E. -0.9396
Precalculus Names: __________
__________
Matching #3
_______ cos 7 A. -1.2360
_______ sec 98 B. 1.0456
_______ cos 304 C. 0.5591
_______ sec 17 D. -7.1852
_______ sec 144 E. 0.9925
Precalculus Names: __________
__________
Matching #4
_______ csc 130 A. -28.653
_______ sin 289 B. 1.3054
_______ sin 185 C. -1.0402
_______ csc 254 D. -0.9455
_______ csc 358 E. -0.0871