Answer :
The expressions of the number of radians can be expressed in the ways below.
How to write the expressions
The radius = 1.9 km
The angular speed = 3.1 radians per hour
a. The expression of t from the number of radians
θ = π/2 + 3.1t
b. Expression from the East
x = rcosθ
= 1.9cos(π/2 + 3.1t)km
c. Expression from the north of the center
= rsinθ
= 1.9sin((π/2 + 3.1t)km
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