A series circuit has only one path for current,
while a parallel circuit has more than one.
The auditory nerve carries an electrical signal to the brain, which turns it into a sound that we recognize and understand.
Let t = Theta and p = Phi
Tan t = y/x Then x =y/Tant.
Tant = y/(x-d) x-d = y/Tanp
y/Tant - d = y/Tanp
y -d*Tanr = y*Tant/Tanp
y-y*Tant/Tanp = d*Tanr
y(1 - Tanr/Tanp = d*Tant
y = d*Tant/(1-Tant/Tanp)