Cos b = 1/2[sin(a+b) + sin (a - b)]
O A. sina
B. sinb
C. cosb
D. cosa

answer: a and c are correct

step-by-step explanation:

the +5 is the vertical translation

the added negative symbol in front is the reflection over the y-axis

14

step-by-step explanation:

14 x 3 = 42

make sure you have version 2.50

try looking in the very back of the book : )

step-by-step explanation:

you can download it here

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.