Answer:
C
Step-by-step explanation:
What makes a function is if each input or x-value has EXACTLY one output or y-value.
a. is wrong because the x value 1, has both an output of 1 and 4
b. is wrong because -1 is repeated 4 times with all different outputs
c. is correct because each input has exactly one output. None of the x values repeat itself
d. is wrong because -1 has 2 outputs.
so this is what makes a function and what doesn't. Hope this helps!
In the half-angle formula for sine and cosine, notice that a plus/minus sign appears in front of each radical (square root). Whether your answer is positive or negative depends on which quadrant the new angle (the half angle) is in
Well $25 is the standard price initially.
$10 is added every hour as a constant rate.
Therefore a. 25 + 10h is the right expression
