There is three sampling frame of students that cannot be sampled in the next Monday. This is Students who are skipping class cannot be sampled, Students who are on a school trip cannot be sampled, and Students who are out sick cannot be sampled.
Write an equation, calling the number x:
3x=2(x+4)
3x=2x+8
x=8
However, 8 is not a perfect square, which was required in the problem, so there are no solutions.
Option A
<em><u>Solution:</u></em>
Given that we have to rewrite with only sin x and cos x
Given is cos 3x
We know that,
Therefore,
---- eqn 1
We know that,
Substituting these values in eqn 1
-------- eqn 2
We know that,
Applying this in above eqn 2, we get
Therefore,
Option A is correct
The equation of a sphere is:
(x – h)^2 + (y – k)^2 + (z – l)^2 = r^2
where h, k and l are the coordinates of the center of the
sphere
Using the midpoint formula, the coordinate of the center
is:
h = (-4 + 6) / 2 = 1
k = (7 + -5) / 2 = 1
l = (6 + 7) / 2 = 6.5
so the equation becomes:
(x – 1)^2 + (y – 1)^2 + (z - 6.5)^2 = r^2
we plug in any point, in this case point P to solve for r:
(-4 -1)^2 + (7 – 1)^2 + (6 - 6.5)^2 = r^2
r^2 = 61.25
So the full equation is:
<span>(x – 1)^2 + (y – 1)^2 + (z - 6.5)^2 = 61.25</span>
