What is an octave? And what does it mean by 1 octave and 2 octaves? Basically I want to play D major , octave 1 what does that mean?

octaves are the higher up or lower down on a scale

coordinates of r(b,c)

slope of nm is 0.

step-by-step explanation:

the midpoint of the line joining the points (x₁,y₁) and (x₂,y₂) is given by

the midpoint of the line segment nk is given by

∴r(b,c)

the slope of the line joining the points (x₁,y₁) and (x₂,y₂) is given by

slope of rs is

hence

coordinates of r(b,c)

and slope of nm is 0.

i would think b and c