Answer:
d) 1.10 + pi
Step-by-step explanation:
You want to know the angle listed whose cosine is not 0.45.
Cos(x) = 0.45
The value of x is found using the inverse cosine function:
x = arccos(0.45) ≈ 1.10
We know that cosine is an even function, so cos(-x) = cos(x). This means the angle can also be ...
x = -1.10
Since the cosine is periodic with period 2π, the values of x can be ...
x = ±1.10 +2nπ, where n is any integer
The value not on this list is ...
1.10 +π
The cosine of that angle is -0.45.
x is not 1.10 +π
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Additional comment
A calculator is useful for sorting this out.
