So, f[x] = 1/4x^2 - 1/2Ln(x)
<span>thus f'[x] = 1/4*2x - 1/2*(1/x) = x/2 - 1/2x </span>
<span>thus f'[x]^2 = (x^2)/4 - 2*(x/2)*(1/2x) + 1/(4x^2) = (x^2)/4 - 1/2 + 1/(4x^2) </span>
<span>thus f'[x]^2 + 1 = (x^2)/4 + 1/2 + 1/(4x^2) = (x/2 + 1/2x)^2 </span>
<span>thus Sqrt[...] = (x/2 + 1/2x) </span>
The coordinates are based on two factors: the x coordinate and the y-coordinate.
The x coordinate is the position of the coordinate horizontally.
The y coordinate is the position of the coordinate vertically.
Berlin is at x-coordinate of 7 and y-coordinate of 8.
Thus the whole coordinate for Berlin is (7,8).
Hope that helped!
The pythagorean theorem works for all right triangles. Just make sure it IS a right triangle.