An "armstrong number" is an n-digit number that is equal to the sum of the nth powers of its individual digits. for example, 153 is an armstrong number because it has 3 digits and 13 + 53 + 33 = 153. what is the digit k in the armstrong number 1,6k4? (a) 2 (b) 3 (c) 4 (d) 5 (e) 6

thus, the first answer choice, y = sec x, is the correct one

let's first notice, the center of the hyperbola is at the origin, since the focus points are equidistantly 3 units away from the origin, that also means that the distance "c" from the center to either focus is 3.

it should also be notable that, the traverse axis for this hyperbola is vertical, or namely over the y-axis and therefore, the positive fraction will be the one with y-variable.

the traverse "a" component or distance from the center to either vertex is not 2, is more than 2, so we can safely put it at √5 ≈ 2.24.