If $380 is invested for one year at 13% simple interest, how much interest is earned?
1 answer:
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Answer:
A
Step-by-step explanation:
We want to solve the equation:
To do so, we can rewrite the equation.
Recall the double-angle for sine:
By substitution:
Distribute:
We can subtract 3cos(x) from both sides:
And factor:
Hence, our answer is A.
*It is important to note that we should not divide both sides by cos(x) to acquire 10sin(x) = 3. This is because we need to find the values of x, and one or more may result in cos(x) = 0, and we cannot divide by 0. Hence, we should subtract and then factor.