According to your description, you can simply plug in all the numbers:
d(47) = 2.15 * 45^2 / (58.4*0.34) = 219.27 m
Apparently my answer was unclear the first time?
The flux of <em>F</em> across <em>S</em> is given by the surface integral,

Parameterize <em>S</em> by the vector-valued function <em>r</em>(<em>u</em>, <em>v</em>) defined by

with 0 ≤ <em>u</em> ≤ π/2 and 0 ≤ <em>v</em> ≤ π/2. Then the surface element is
d<em>S</em> = <em>n</em> • d<em>S</em>
where <em>n</em> is the normal vector to the surface. Take it to be

The surface element reduces to


so that it points toward the origin at any point on <em>S</em>.
Then the integral with respect to <em>u</em> and <em>v</em> is



First, factor the expression on the top. What two numbers add to get 8 and multiply to 15? 5 and 3! so the top expression factors to (x+3)(x+5). You can cancel the x+3 from the denominator and end up with x+5. Make sense?
Hello there!
To find the zeroes or the roots of a function, you just need to set the function equal to 0 then solve for x
f(x) = 2x² - 8x - 10
Set function equal to 0
2x² - 8x - 10 = 0
Now we can factorize the left side
2(x + 1)(x - 5) = 0
Then set factors equal to 0
x + 1 = 0 or x - 5 = 0
x = 0 - 1 or x = 0 + 5
x = -1 or x = 5
Thus,
The roots are -1 and 5
Let me know if you have any questions. As always, it is my pleasure to help students like you~!