Question

prove :
(1+sina-cosa)2=2(1+sina)(1-cosa)

Answer 1

Answer:

the smallest group of atoms which has the overall symmetry of a crystal, and from which the entire lattice can be built up by repetition in three dimensions.

Answer 2

(1−sinA+cosA)

2

=1+sin

2

A+cos

2

A−2sinA+2cosA−2sinAcosA

=2−2sinA+2cosA−2sinAcosA

Considering RHS:

2(1−sinA)(1+cosA)=2(1+cosA−sinA−sinAcosA)

=2+2cosA−2sinA−2sinAcosA

2−2sinA+2cosA−2sinAcosA=2+2cosA−2sinA−2sinAcosA