The answer:
the main formula of the circle's equation is
(x-a)²+ (y-b)² = R²
where C(a, b) is the center of the circle
R is the radius
if a point A(x', y') passes through the circle, so the equation of the circle can be written as
(x'-a)²+ (y'-b)² = R², and that is a main formula.
<span>Circle O, with center (x, y), passes through the points A(0, 0), B(–3, 0), and C(1, 2), so we have exactly three equation:
</span>
(0-x)² + (0-y)² = R², circle O passes through A
x²+y²= R²
(-3 -x)² + (0-y)² = R², circle O passes through B
(-3 -x)² + (y)² = R²
(1-x)² + (2-y)² = R², circle O passes through A
(1-x)² + (2-y)² = R²
and we know that R= OA = OC= OB,
OA=R= sqrt( (0-x)² + (0-y)² ) = OB = sqrt((-3 -x)² + (0-y)²), this implies
x²+y² = (-3 -x)² + (0-y)² , it implies x² = 9+ x² + 6x , and then -9/6=x, x= -3/2
and when OA = OC
x²+y² =(1-x)² + (2-y)² so, x²+y² =1+x²-2x +4+y²-4y, therefore -5= -2x -4y
-5= -2x -4y, when x = -3 /2 we obtain y = 2
the center is C(-3/2, 2)
For future reference, you could use Desmos for graphs. but should be (1,1)
Answer:
Percentage of scores that fall between 70 and 80 = 24.34%
Step-by-step explanation:
We are given a test with a population mean of 75 and standard deviation equal to 16.
Let X = Percentage of scores
Since, X ~ N(
)
The z probability is given by;
Z = 
~ N(0,1) where, 
= 75 and 
= 16
So, P(70 < X < 80) = P(X < 80) - P(X <= 70)
P(X < 80) = P( < 
) = P(Z < 0.31) = 0.62172
P(X <= 70) = P( < 
) = P(Z < -0.31) = 1 - P(Z <= 0.31)
= 1 - 0.62172 = 0.37828
Therefore, P(70 < X < 80) = 0.62172 - 0.37828 = 0.24344 or 24.34%
I am pretty sure the answer is C.
A conjecture is a statement that you believe to be true, and that has be verified by your observations, not necessarily exhaustively. That is to say, your conjecture may not even be true, although you believe that it is.
If we denote by S the sum of the first 30 positive even numbers, we could make many conjectures, such as:
S is even
S is positive,
S=930
S is composite
.... etc.
