Add math doubt...astar plz help

[Theguitarist]

the definition of a unit vector is essentially one which has a magnitude of 1. so if i had a vector i+j, the unit vector would be (i+j) / root 2. Root 2 is obtained by doing a square root of 1 squared + 1 squared (because it is 1i+1j i.e i+j). so it is basically the vector itself divided by its magnitude.

[Ghost Of Highbury]

hey thanks the guitarist
appreciated

[astarmathsandphysics]

A(7,2) C(1,4) are two vertices of a square ABCD
(a)find the equation of the diagonol BD
(b) Find the coordinates of B and of D

a) gradient of AC=m=(4-2)/(1-7)=-1/3 Now use y-y₁=m(x-x₁)

y-2=-1/3(x-7) so y=-1/3x+13/3

AC=(-6,2) and BD is at right angles so BD=(2.6) so from centre to B=(1,3) and to D=(-1,-3). Ccentre is at midpoint of AC=1/2(7+1,2+4)=(4,3)  so B=(1,3)+(4,3)=(5,6) and C=(-1,-3)+(4,3)=(3,0)