Answer:
1) -0.669
2) -0.669
3) 0.669
Step-by-step explanation:
Since we are subtracting or adding multipled of pi, we will either obtain 0.669 or -0.669 as our answer for each of the three different questions.
Cosine is the x-coordinate in our orderes pairs. If our point ends up on the right side of the y-axis, the cosine will be positive. If our point ends up on left side, it will be negative.
Choose a thetha (I'm going to choose it in degrees) in the first quadrant to help with a visual.
If theta=70:
1) then 180-70=110 which is in second quadrant, so our cosines will be opposite in value.
2) then 180+70=250 which is in third quadrant, so our cosines will be opposite in value.
3) then 4×180-70=720-70=650 =1(360)+290 which ends up in the 4th quadrant which means the consines will have the same value.
What figure are we looking for?
Answer:
Step-by-step explanation:
We will use the work form of a quadratic to determine what a is...in fact we will write the equation for the whole thing in the process, because it's part of solving for a.
y = ±|a|(x - h)² + k
where x and y are from a coordinate point on the graph, h and k are the coordinates of the vertex, the absolute value of a indicates how steep or flat the graph is compared to the parent graph, and the ± is because a positive parabola opens up and a negative one opens upside down.
The vertex is (0, 9) and the coordinate point I chose to use is (3, 0). Filling those in and solving for a:
0 = ±|a|(3 - 0)² + 9 and
0 = ±|a|(3)² + 9 and
-9 = ±|a|9 and
-1 = ±|a| so a = 1. Because this is an upside down parabola the negative is out front, but a is independent of it. The correct choice is C. The quadratic function is
or in more detailed form: