The velocity is the derivative of position.
... v(t) = r'(t) = -5sin(t)i +4cos(t)j . . . . velocity
The acceleration is the derivative of velocity.
... a(t) = v'(t) = -5cos(t)i -4sin(t)j . . . . acceleration
The speed is the magnitude of velocity.
... s(t) = ||v(t|| = √((-5sin(t))² +(4cos(t))²)
... = √(25sin(t)² +16(1 -sin(t)²))
... s(t) = √(16 +9sin(t)²) . . . . speed
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Of course, derivatives of these functions are found from ...
... (d/dt)(sin(t)) = cos(t); (d/dt)(cos(t)) = -sin(t); (d/dt)(a + b) = da/dt + db/dt.
Answer:
B. High optical density, and light travels more slowly through it.
Step-by-step explanation:
Refractive index is the property of a material that describes the change in the initial path of light and the rate at which light travels through it. And optical density of a material describes its absorption ability to rays or beam of light passing through it.
As the index of refraction of a material increases, therefore its optical density would increase. This would cause light to travel through it slowly. Unless the light has a high frequency.
A material with a high index of refraction has a high optical density, and light travels more slowly through it.
Dude you distribute.3(x+3)
That equals.3x+.9!!!!
So we solve for each
70% of 100=70
students who didn't buy lunch=100-70=30
some of the 70 left so that the students who bought lunch, are 60% of those who are left
we know that the students who didn't buy lunch didn't change number so therefor
100% of students left-60%=40%= students that didn't buy lunch=30 so
40%=30
20%=15
100%=75
there were 75 students lfet in the cafeteria