SOLUTION: Picture yourself in a ’special’ world where {{{c^2+s^2=1}}} Under this assumption, select the true statement/s: A) Every {{{1 + (s^2)/(c^2)}}} can be ’exchanged’ fo

Picture yourself in a ’special’ world where 

Under this assumption, select the true statement/s:
We try out each possibility:


A) Every 

 

can be ’exchanged’ for 



We see if this equation

is equivalent to the original.
We multiply through by the common denominator c²



That is the correct choice.  But let's see why the other one is not correct


B) Every 

 

can be ’exchanged’ for 



We see if this equation

is equivalent to the original.
We multiply through by the common denominator c²




And even if I subtract s² from both sides, I get

that is not the same as the original.
So A) is the only correct answer.

Edwin
 

Edwin made a mistake in B)

The way I did it was: 

We need to determine IF: 

                          ------ Substituting 

                         

                          <====== As you can clearly see, this is TRUE!