I got u with this it really easy
To find the diameter, you use the formula: 2x. we use 2x because the radius is 2 times the diameter.
so, if the radius is 3,980, then we substitute that into the formula.
2(3,980)
this will give us 7960. the diameter is 7960 miles.
Answer:
6 knots
Step-by-step explanation:
Let the speed be v knots
then time taken to cover 500 M = 500 / v hrs
fuel consumption /hr = 216 + 0.5v^3
let F be the fuel consumption for trip
= [500/v][216 + 0.5v^3]
= 500[216/v + 0.5v^2]
dF/dv = 500[ - 216/v^2 + v]
d^2F/d^2v = 500[432/v^3 + 1] , i.e. +ve
so setting dF/dv will give a minima
500[ -216/v^2 + v] = 0
or v = 216/v^2
or v^3 = 216
solving, we get v = [216]^(1/3) = 6 knots
We know that
Any point <span>(x,y)</span> on the parabola is equidistant from the focus and the directrix
Therefore,
focus (0,4) and directrix of y=2
<span>√[<span>(x−0)</span></span>²+(y−4)²]=y−(2)
<span>√[x</span>²+(y-4)²]=y-2
x²+(y-4)²=(y-2)²
x²+y²-8y+16=y²-4y+4
x²=4y-12-----> 4y=x²+12----->y= (x²/4)+3
the answer is
y= (x²/4)+3
