Step-by-step explanation:
explain step by step on photo, double check just in case
Answer:
Step-by-step explanation:
cos (x/2)=cos x+1
cos (x/2)=2cos ²(x/2)
2 cos²(x/2)-cos (x/2)=0
cos (x/2)[2 cos (x/2)-1]=0
cos (x/2)=0=cos π/2,cos (3π/2)=cos (2nπ+π/2),cos(2nπ+3π/2)
x/2=2nπ+π/2,2nπ+3π/2
x=4nπ+π,4nπ+3π
n=0,1,2,...
x=π,3π
or x=180°,540°,...
180°∈[0,360]
so x=180°
or
2cos(x/2)-1=0
cos (x/2)=1/2=cos60,cos (360-60)=cos 60,cos 300=cos (360n+60),cos (360n+300)
x/2=360n+60,360n+300
x=720n+120,720n+300
n=0,1,2,...
x=120,300,840,1020,...
only 120° and 300° ∈[0,360°]
Hence x=120°,180°,300°
It should be 715, i don’t understand why that isn’t one of the choices.
you’re supposed to multiply everything
The total length of red and blue ribbons is 10.2 m.
Given that, the length of the red ribbon =2.4 m and the length of the blue ribbon =7.8 m.
<h3>How to add two decimals?</h3>
Adding decimals is similar to the usual addition of whole numbers. We know that a decimal number is a number with a whole number part and a fractional part which is separated by a decimal point.
Now, the length of the red ribbon + the length of the blue ribbon=2.4+7.8
=10.2 m
Therefore, the total length of red and blue ribbons is 10.2 m.
To learn more about the addition of decimals visit:
brainly.com/question/17612968.
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I assume the answer is 1/4
