PLZ i want the answer
1 answer:
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Answer:
see explanation
Step-by-step explanation:
Given that M is directly proportional to r³ then the equation relating them is
M = kr³ ← k is the constant of proportion
To find k use the condition when r = 4, M = 160, thus
160 = k × 4³ = 64k ( divide both sides by 64 )
2.5 = k
M = 2.5r³ ← equation of variation
(a)
When r = 2, then
M = 2.5 × 2³ = 2.5 × 8 = 20
(b)
When M = 540, then
540 = 2.5r³ ( divide both sides by 2.5 )_
216 = r³ ( take the cube root of both sides )
r = = 6
Answer:
Step-by-step explanation:
The directrix y=-6 is parallel to the x axes, so parabola has equation of the form
where is the vertex of parabola and p is parabola's parameter.
By the definition, is the distance from the vertex to the directrix, so
Hence, the equation of parabola is
See attached diagram for the graph of parabola and its directrix.
In vertex form this equation is
