Cracking the SAT Physics Subject Test

around 500 B.C. Some rules

of his number-worshipping

group included prohibitions

against eating beans and

wearing wool.

Now for the trig functions. Let’s consider angle A in the right triangle pictured on
the previous page. The sine, cosine, and tangent of this angle are defined like this:

By opposite we mean the length of the side that’s opposite the angle, and by
adjacent we mean the length of the side that’s adjacent to the angle. The same
definitions, in words, can be used for angle B as follows:

Notice that sin A = cos B and cos A = sin B.

SOHCAHTOA

Here’s a word you should remember on test day so you can keep clear on

the definitions of sin θ, cos θ, and tan θ: SOHCAHTOA. This isn’t some

magic word to chant over your test booklet; it simply helps you remember

that

Sine = Opposite side over Hypotenuse (S = )

Cosine = Adjacent side over Hypotenuse (C = )