Study questions platform-wide or filter by specific tests with correct answers revealed.
In the $xy$-plane, circle $C$ has center at $(-6,\ -7)$. The point $(-6,\ 5)$ lies inside the circle, and the point $(8,\ -7)$ lies outside the circle. If the radius $m$ of circle $C$ is an integer, what is the value of $m$?
The distance from the center $(-6, -7)$ to the inside point $(-6, 5)$:
$d_1 = \sqrt{(-6-(-6))^2 + (5-(-7))^2} = \sqrt{0 + 144} = 12$
Since $(-6, 5)$ is inside the circle: $m > 12$.
The distance from the center $(-6, -7)$ to the outside point $(8, -7)$:
$d_2 = \sqrt{(8-(-6))^2 + (-7-(-7))^2} = \sqrt{196 + 0} = 14$
Since $(8, -7)$ is outside the circle: $m < 14$.
So $12 < m < 14$, and $m$ is an integer, therefore $m = \mathbf{13}$.
- \(25 = 5^2\)
- \(30 = 2 \times 3 \times 5\)
- \(35 = 5 \times 7\)
- \(40 = 2^3 \times 5\)
Square Pyramid analysis:
- Top view: A square base with diagonals β appears as a square β
- Front view: Triangular elevation β
- Side view: Triangular elevation β
A cone would give a circular top view. A triangular prism would give a rectangular side view. A cylinder gives circular front/side views.
All three views match a square pyramid perfectly.
Find the value of $\displaystyle\int_{-\pi/2}^{\pi/2}\dfrac{\sin^2 x}{1+2^x}\,dx$
Let $I=\displaystyle\int_{-\pi/2}^{\pi/2}\dfrac{\sin^2x}{1+2^x}dx$. Use the property $\int_{-a}^a f(x)dx$: replace $x\to-x$:
$I=\displaystyle\int_{-\pi/2}^{\pi/2}\dfrac{\sin^2x}{1+2^{-x}}dx=\displaystyle\int_{-\pi/2}^{\pi/2}\dfrac{2^x\sin^2x}{1+2^x}dx$
Adding: $2I=\displaystyle\int_{-\pi/2}^{\pi/2}\sin^2x\,dx=\displaystyle\int_{-\pi/2}^{\pi/2}\dfrac{1-\cos2x}{2}dx=\dfrac{\pi}{2}$
$I=\dfrac{\pi}{4}$
The active mass movement of mitochondria and other organelles in the cytoplasm is due to:
Cyclosis (cytoplasmic streaming) is the directed flow of cytosol that moves organelles like mitochondria. It is driven by actin-myosin interactions.
Sign in to join the conversation and share your thoughts.
Log In to Comment