Determine if the following sets are subspaces of R n×n under the usual operations.

(a) The set of all upper triangular matrices.

(b) The set of all symmetric matrices.

(c) The set of all orthogonal matrices.

(d) The set of all matrices A such that A2 = 0.​

a. 12.5 kg

step-by-step explanation:

f = ma

so

m = f/a = (2500 n)/(200 m/s²) = 12.5 kg

1 n = 1 kg·m/s²

isaiah walks 3 miles due north, turns and then 5 miles due east. how far is he from his starting point?

a^2 + b^2 = c^2

let c = distance from starting point.

(3)^2 + (5)^2 = c^2

9 + 25 = c^2

34 = c^2

sqrt{34} = sqrt{c^2}

sqrt{34} = c