Page 91 - Math SL HB Sem 1

CIRCULAIT F'UNCTIONS AND TIUGON()]!IE'I'RY

'lL::"^"1"
lhree orher rrigonometric ratios knorvn as the reciprocal trigonometric
ratlos: cosecant,secant and cotangent ratios. .fhese
are delined as
: l,
.r" B sin d;.0
srn d

sec d , cos 0 *0
cos d

.o1 B:1,@n0*0
tan 0

ANGLE OF ANY MAGNITUDE

'fhe
first quadrant (acute angles)
p
On the unit circle, if lAOp: do, then the coordinates of are (cosd, sind)

v
(r, y) = (cos ,, sio ,)

radian measure of
I the angle 6
I
I

0 x:cosd
y=sin0

The second quadrant (obtuse angles)

g
We will apply the definitions for sin d and cos to obluse angles
:
srn l50o sin . . ... . (in radians) :
:
sin 30o sin......

cosl50o : cos..... . (in radians; =

:
cos 30o cos....-..

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