cos (2x) = cos x
2 cos^2 x -1 = cos x using the double angle formula
2 cos ^2 x -cos x -1 =0
factor
(2 cos x+1) ( cos x -1) = 0
using the zero product property
2 cos x+1 =0 cos x -1 =0
2 cos x = -1 cos x =1
cos x = -1/2 cos x=1
taking the arccos of each side
arccos cos x = arccos (-1/2) arccos cos x = arccos 1
x = 120 degrees x=-120 degrees x=0
remember you get 2 values ( 2nd and 3rd quadrant)
these are the principal values
now we need to add 360
x = 120+ 360n x=-120+ 360n x = 0 + 360n where n is an integer
Answer:
48 minutes
Step-by-step explanation:
First do 3 divided by 3/4 and that gives you 4. Then multiply 4 by 12 and you get 48.
Splitting up the interval of integration into 
subintervals gives the partition
![\left[0,\dfrac1n\right],\left[\dfrac1n,\dfrac2n\right],\ldots,\left[\dfrac{n-1}n,1\right]](https://tex.z-dn.net/?f=%5Cleft%5B0%2C%5Cdfrac1n%5Cright%5D%2C%5Cleft%5B%5Cdfrac1n%2C%5Cdfrac2n%5Cright%5D%2C%5Cldots%2C%5Cleft%5B%5Cdfrac%7Bn-1%7Dn%2C1%5Cright%5D)
Each subinterval has length 
. The right endpoints of each subinterval follow the sequence
with 
. Then the left-endpoint Riemann sum that approximates the definite integral is
and taking the limit as 
gives the area exactly. We have
We are given 
The order of the letter sequence is important. The letters pair up based on how they are arranged. We see that A and E are the first letters of the sequences. So this means that angles A and E are the same measure
angle A = angle E
3x+20 = 5x-80
3x-5x = -80-20
-2x = -100
x = -100/(-2)
x = 50
Use this x value to find the measure of angle A
angle A = 3x+20
angle A = 3(50)+20
angle A = 150+20
angle A = 170 degrees
<h3>Therefore, the statement "the measure of angle A is 45 degrees" is <u>false</u>.</h3>
