a angle AOP= (180o¡μ)
biPis(cos(180o¡μ),sin(180o¡μ))
ii Pis(¡cosμ,sinμ)
c cos(180o¡μ)=¡cosμ and sin(180o¡μ) = sinμ
d tan(180o¡μ)=
sin(180o¡μ)
cos(180o¡μ)
=
sinμ
¡cosμ
fusingcg
=¡tanμ
EXERCISE 29A.1
1a
b Find the coordinates of P correct to 3 decimal places.
2 Use the unit circle diagram to find:
a sin 180o b cos 180o c sin 270o d cos 270o
e cos 360o f sin 360o g cos 450o h sin 450o
3 Use the unit circle diagram to estimate, to 2 decimal places:
a cos 50o b sin 50o c cos 110o d sin 110o
e sin 170o f cos 170o g sin 230o h cos 230o
i cos 320o j sin 320o k cos(¡ 30 o) l sin(¡ 30 o)
4 Check your answers to 3 using your calculator.
tanμ=
sinμ
cosμ
5aState the coordinates of point P.
b Find the coordinates of Q using:
i the unit circle
ii symmetry in thex-axis.
c What can be deduced fromb?
d Usecto simplifytan(¡μ):
6 By considering a unit circle diagram like that in 5 , show how to simplify
sin(180o+μ), cos(180o+μ), and tan(180o+μ).
Hint: Consider rotational symmetry.
x
y
O 1
1
-1
-1
231°
P
x
y
O 1
A
1
-1
-1
q
P
-q Q
State the exact coordinates of P.
Further trigonometry (Chapter 29) 581
IGCSE01
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Y:\HAESE\IGCSE01\IG01_29\581IGCSE01_29.CDR Monday, 27 October 2008 2:52:32 PM PETER