In triangles A¢B¢P and ABP, we have,
B A
B P
BA
BP
′
′
′
=
With the sign convention, this becomes
Rationalised 2023-24
Physics
226
–
–
h
v
h
u
′ = –
so that
m = 
–
h
v
h
u
′ =
(9 9)
We have derived here the mirror equation, Eq (9 7), and the
magnification formula, Eq