-1 (-12 - 9i) + 4i (-12 - 9i)
= 12 + 9i + -48i + 9i^2
= 9i^2 + 39i + 12
Step-by-step explanation:
cos(3x) − 3 cos x = cos(2x) + 1
Use triple and double angle formulas.
(4 cos³x − 3 cos x) − 3 cos x = (2 cos²x − 1) + 1
Simplify.
4 cos³x − 6 cos x = 2 cos²x
4 cos³x − 2 cos²x − 6 cos x = 0
2 cos³x − cos²x − 3 cos x = 0
Factor.
cos x (2 cos²x − cos x − 3) = 0
cos x (cos x + 1) (2 cos x − 3) = 0
Solve.
cos x = 0 → x = 90°, 270°
cos x + 1 = 0 → x = 180°
2 cos x − 3 = 0 → no solution
Answer:
A.) The function is increasing for all real values of x where x < -4
Step-by-step explanation:
On the interval x < -4, all of the x values are increasing. Before x = -4, the line assumes a positive slope because it is heading upwards. After this interval, the function is decreasing because the slope is heading downwards.
On the interval -6 < x < -2, all of the x values are positive because they lie above the x-axis. This does not necessarily mean that all of the values are increasing.
On the interval x < -6 and x > -2, all of the x values are negative because they lie below the x-axis.
Answer:
ohhhhhhhhhhhhhhhhh <em><u>8====></u></em> have a good day
Answer:
4) smaller number is 9, larger number is 12
13) 38.45=5m+8.5
m=5.99
Step-by-step explanation:
x+y=21 the sum of two numbers is 21
x-3=.5y the smaller number is 3 more than half the larger number
multiply both sides by 2 and you get 2x-6=y
plug that equation into the first equation and you get x+2x-6=21
simplifying you get 3x-6=21 add 6 to both sides and you get 3x=27
x=9 so the smaller number is 9 then you plug that back into the first equation and get y=12
let m be the cost of 1 movie and c be the cost of the cd
38.45=5m+c
38.45=5m+8.5 this is the equation you use
subtract 8.5 from both sides and you get 29.95=5m
divide both sides by 5
5.99=m the answer