Answer:
Explanation:
Given a square Piece whose side is 12 inches
Now square pieces are cut from each corner to make it a open box
Suppose x is the length of square piece at each corner
then
base square has a length of 
Dimension of new box is 
Volume 

For maximum volume differentiate with respect to x we get

we get x=6 and 4 but at x=6 volume becomes zero therefore x=4 is valid



Answer:
The function has a maximum in 
The maximum is:

Explanation:
Find the first derivative of the function for the inflection point, then equal to zero and solve for x




Now find the second derivative of the function and evaluate at x = 3.
If
the function has a maximum
If
the function has a minimum

Note that:

the function has a maximum in 
The maximum is:

Answer:
X-rays travel through space faster than radio waves.
Explanation:
Electromagnetic waves consist of oscillations of the electric and the magnetic field in a plane perpendicular to the direction of motion the wave.
All electromagnetic waves travel in a vacuum always at the same speed, the speed of light, whose value is:

Electromagnetic waves are classified into 7 different types, according to their wavelength/frequency. From shortest to longest wavelength (and so, from highest to lowest frequency), we have:
Gamma rays
X rays
Ultraviolet
Visible light
Infrared radiation
Microwaves
Radio waves
Now we can analyze the 4 statements:
X-rays and radio waves are both forms of light, or electromagnetic radiation --> TRUE. They are both types of electromagnetic waves.
X-rays have higher frequency than radio waves. --> TRUE, as we can see from the table above.
X-rays have shorter wavelengths than radio waves. --> TRUE, as we can see from the table above.
X-rays travel through space faster than radio waves. --> FALSE: all electromagnetic waves travel in space at the same speed, the speed of light.
Gravitational field exists in
the space surrounding a charged particle and exerts a force on other charged
particles. Gravitational waves are ripples of waves travelling outward from the
source. The more massive the orbit of two bodies, the more it emits
gravitational wave. And everything around it that is near within the wave
experiences a ‘pull’ toward the orbiting bodies.