Answer:
a variable
Step-by-step explanation:
a variable.
The infinite series description of trig functions is much neater when the argument is radians. For example, for small angles, sin(x) ≈ x when x is in radians. You could say that radians is the "natural" measurement unit for angles, just as "e" is the "natural" base of logarithms.
If the angle measure were degrees or grads or arcseconds, obnoxious scale factors would show up everywhere.
Answer:
A
Step-by-step explanation:
A is the only equation that does not account for the fact that Tu bought 2 tickets and 2 drinks.
The rest do: B subtracts the appropriate amounts twice, C multiplies the doubled expenses, and D does the same, just the amount paid is also separated.