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Who remembers the Trig
Functions?

Cosine


Sine
Tangent
Basic definitions
In this right triangle: sin(A) = a/c; cos(A) = b/c;
tan(A) = a/b.
The shape of a right triangle is completely
determined, up to similarity, by the value of either of
the other two angles.
This means that once one of the other angles is
known, the ratios of the various sides are always the
same regardless of the size of the triangle.
These ratios are traditionally described by the
following trigonometric functions of the known angle:
(2007). Trigonometry. Retrieved February 5, 2007, from Wikipedia: The Free Encyclopedia
Web site: http://en.wikipedia.org/wiki/Trigonometry
The sine function (sin), defined as the ratio of
the leg opposite the angle to the hypotenuse.
The cosine function (cos), defined as the ratio of
the adjacent leg to the hypotenuse.
The tangent function (tan), defined as the ratio
of the opposite leg to the adjacent leg.
The adjacent leg is the side of the angle that is
not the hypotenuse.
The hypotenuse is the side opposite to the 90
degree angle in a right triangle; it is the longest
side of the triangle. (2007). Trigonometry. Retrieved February 5, 2007, from
Wikipedia: The Free Encyclopedia Web site: http://en.wikipedia.org/wiki/Trigonometry
Trig Functions
In this right triangle: sin(A) = a/c;
cos(A) = b/c; tan(A) = a/b.
(2007). Trigonometry. Retrieved February 5, 2007, from Wikipedia: The
Free Encyclopedia Web site: http://en.wikipedia.org/wiki/Trigonometry
When will we use trig?

http://teachertube.
com/viewVideo.ph
p?video_id=10006
5&title=Using_Trig
_in_Real_Life
Do you a have a creative way to
remember the ratios?
The sine, cosine and tangent ratios in right
triangles can be remembered by
SOH CAH TOA (sine-opposite-hypotenuse
cosine-adjacent-hypotenuse tangentopposite-adjacent).
It is commonly referred to as "Sohcahtoa" by
some American mathematics teachers, who
liken it to a (nonexistent) Native American
girl's or mountain's name.
(2007). Trigonometry. Retrieved February 5, 2007, from Wikipedia: The Free
Encyclopedia Web site: http://en.wikipedia.org/wiki/Trigonometry
What about a 45°-45°-90° Δ
A
Sin<A =
1
2
C
Cos<A =
B
1
Tan<A =
You can find the sin, cos and tan of either angle.
Find them for <B.
The angle can be named <A or sin 45°
What about a 30°-60°-90° Δ ?
B
2
1
C
Sin<A =
3
A
Cos<A =
Tan<A =
Try this one!
B
6
3
C
3 3
A
Look for a pattern:
If you find out that the sine of an
angle is equal to .5 or ½, what
can you say about the angle?
What can you say about the
triangle if it has a right angle?
If the sine of one angle is ½ and the triangle is
a right triangle, you have a 30-60-90 triangle.
Learn these!!!!