Answer:
cos(a + b) = 
Step-by-step explanation:
cos(a + b) = cos(a).cos(b) - sin(a).sin(b) [Identity]
cos(a) = 
cos(b) = 
Since, terminal side of angle 'a' lies in quadrant 3, sine of angle 'a' will be negative.
sin(a) =
[Since, sin(a) =
]
= 
= 
Similarly, terminal side of angle 'b' lies in quadrant 2, sine of angle 'b' will be negative.
sin(b) =
= 
= 
By substituting these values in the identity,
cos(a + b) = 
= 
= 
= 
Therefore, cos(a + b) = 
Answer:
45
Step-by-step explanation:
<ABY=<ZBY(VERTICAL ANGLES)
SO.
3x-5=2x+40
3x-2x=40+5
x=45
1) -16 = v - 14
Add 14 to both sides.
v = -2
2) -2n = -22
Divide both sides by -2.
n = 11
3) 25 = b + 7
Subtract 7 from both sides.
b = 18
Answer:
70
Step-by-step explanation:
complementary angles are 2 angles that add up to 90, the first angle is already 20 so just subtract 90-20 to find other angle