Answer:
steps below
Step-by-step explanation:
Are you going to solve the value of A or just a proof the equation
cos 2A = cos² A - sin² A
2cos²A-cos2A-1 = 2cos²A - (cos² A - sin² A) - 1 = cos² A + sin² A - 1
2cos²A-cos2A-1 = 1 - 1 = 0
A: 90° or 270° or 450° .....
Answer:
36years
Step-by-step explanation:
Let charity present age be x
Charity daughter present age be y
Charity husband present age be z
If the sum of their ages ten years to come is 117, then;
10+x+10+y+10+z = 117
30+x+y+z = 117
x+y+z = 87 ... 1
If charity is four times as old as her daughter, then;
x = 4y
y = x/4 ... 2
If she is also six years younger than her husband, then;
x = z- 6
z = x+6 .. 3
Substitute 2 and 3 into 1;
x + x/4 + (x+6) = 87
Multiply through by 4
4x + x + 4(x+6) = 4(87)
5x+4x+24 = 348
9x = 348 - 24
9x = 324
x = 324/9
x = 36
hence Charity is 36years old today
Let's assume the opposite is the case. So let's assume that a = b is true. If so, then f(a) and f(b) would be the same output. This is because we can replace 'b' with 'a', or vice versa. In other words, f(a) = f(b) would be true. But this contradicts the original inequality that f(b) < f(a)
So that is why 'a' cannot equal b. We don't know if a > b or if a < b (unless we are told if the function is strictly decreasing or increasing on the interval from x = a to x = b), so we just leave it as 
Answer:
m:is the slope b:y intercept equation:y=mx+6
Step-by-step explanation: