precalculus help

Question

An alternating current i in amperes in another circuit can be found after t seconds using i=4sin(195∘t)

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 Rewrite the formula in terms of the difference of two angle measures.

Select one:

a. 4sin(30∘t−225∘t)

b. 14sin(225∘t−30∘t)

c. 14sin(30∘t−225∘t)

d. 4sin(225∘t−30∘t)

Answer 1

Hi Morgan G.,

For i = 4sin(195*t):

a.) 4sin(30*t - 225*t) = 4sin(-195*t) = -4sin(195*t), the amplitude of -4 is incorrect.

b.) 14sin(225*t - 30*t) = 14sin(195*t), the amplitude of 14 is incorrect.

c.) 14sin(30*t - 225*t) = 14sin(-195*t) = -14sin(195*t), the amplitude of -14 is incorrect.

d.) 4sin(225*t - 30*t) = 4sin(195*t), this is the correct i.

I hope this helps, Joe.