Verify the identity 1 = cot2x sec2 x – cot2 x
cot2x sec2 x – cot2 x =
cot2x (sec2 x – 1) =
cot2x (tan2x) =
1
A. sin
B. cos
C. cot
D. tan
E. csc
F. sec
cos  sec 

cot 
sec  cot  
A. sin
B. cos
C. cot
D. tan
E. csc
F. sec

Sin(x +  ) = cos x
2

sin( x  )
2
 sin x  cos

 cos x  sin
2
 sin x  (0)  cos x  (1)
 cos x

2
cos12 cos 45  sin 12 sin 45
cos 57
sin 45 cos13  cos 45 sin 13
sin 32
cos( x 

6
)  cos x  cos

6
 sin x  sin

6
24 3
1


 sin x 
25 2
2
24 3  7 1




25 2
25 2
r=25
(24, -7 )
x is in quadrant four
24 3  7

50

sin   cos   cos   sin 
2 2
 sin   cos   ( )( )
5 3
21 5 2 2


 ( )( )
5
3
5 3
Sin (α + β)=
(2,
21 )
r=5
(
r=3
5 , 2)
105  4

15




Sin 2x = 2 sin x cos x
Cos 2x = cos2 x – sin2 x
= 1 – 2 sin2 x
= 2 cos2 x – 1
2 tan x
tan 2 x 
2
1  tan x
Find tan 2x
7
5
x
 20 6

Sin 2α

Cos 2α

Tan 2α

65
97


72
97
65
72

Quiz Tuesday on the formulas