How to factor by grouping:
1 answer:
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Answer:
Step-by-step explanation:
Consider a sketch of the problem as shown in the picture, where:
- Blue line is given by y = 4x + 1.
- Point B is the center of the circle.
- Point A is (-3, 0).
Since the center of the circle lies on the line y = 4x +1 and is tangent to the x-axis at point A, then its radius BA is perpendicular to the x-axis. To find the coordinates of point B, we must replace x = -3 into the blue line equation: y = 4x(-3) + 1 = -11.
So, we know that the center of the circle is at B=(-3, -11). And furthermore, the radius BA is of length r=11.
Since the <em>general equation of the circle</em> of radius lenght r centered at (h, k) is given by
then with h = -3, k = -11 and r= 11, the equation of our circle is
Answer:
10β
Step-by-step explanation:
We can find this two ways, first by seeing in the step after it, cosines are canceled out. Since you already have 10β
on the next step, you can assume that (since only the cosines changed and the cosine next ot the blank was removed), the value is 10
β
.
You can also use double angle formulas from the previous step:
(sin(2β) = 2 sin(β) cos(β))and find that:
5 sin (2β) sin(β) = 5 * (2 sin(β) cos(β)) sin(β)) = (10 sin(β) sin(β)) cos(β) =
10β
cos(β)
But since cos(β) is already present, we can see that the answer is 10β