Question

A mountaintop is a height
y
above the level ground. A woman measures the angle of elevation of the
mountaintop to be
θ
when she is a horizontal distance
x
from the mountaintop.
After walking a
distance
d
close
r to the mountain, she measures the angle of elevation of the mountaintop to be
φ
.
Neglecting the height of the woman’s eyes above the ground, find an expression for the height of the
mountain,
y
, in terms of
d
,
φ
, and
θ
. Note that your expression cannot
contain
x