Answer:
21. C, 24.B
Step-by-step explanation:
Since the y-value for x = 0 is not zero, the function cannot have sine in it because sin of 0 is always 0. Therefore, the function will have cos in it. That leaves only B and C left. Since cos(0) is always 1, and the value of y when x = 0 is 0.5, the function will have 1/2 multiplied by a cos function. The only answer option that has that is C.
Now, for the next problem, we know the values of all three sides, and we need to find one angle. We can use the law of cosines for this and plug the values into the equation:
[tex]55^2=40^2+24^2-2(40)(24)\cos(C)[/tex]
We can subtract 40 squared plus 24 squared from both sides to get
[tex]849=-2(40)(24)\cos(C)[/tex]
Negative two times 40 times 24 equals -1920. Dividing -1920 from both sides gets us
[tex]\frac{849}{-1920}=\cos(C)[/tex]
Plugging this equation into a calculator and solving for C, we get the answer as approximately
C = 116.24353.
This rounds to 116.2
