Question

(cos alpha -cos beta) square + (sin alpha - sin beta) square​

Answer 1

2-2(cosalphacosbetta+sinalphasinbetta)

Answer 2

let alpha be a

beta be b

for convenience

(cosa-cosb)*2+(sina-sinb)*2

=cos*2(a)+cos*2(b)-2cos(a)cos(b)+sin*2(a)+sin*2(b)-2sin(a)sin(b)

now (cos*2x+sin*2x=1)

1+1-2{cos(a)cos(b)+sin(a)sin(b)}

====2-2{cos(a-b)}=====