For the given equation ⇒⇒⇒ [tex] \frac{sin \ 2x}{cos \ x} =2[/tex]
and the given range 0 ≤ x ≤ π
We should note that the zeros of the denominator will be at
cos x = 0
∴ [tex]x = cos^{-1} 0 = \frac{\pi}{2} [/tex]
So, the given equation is undefined at π/2
So, the students error is the division by zero.
See the attached figure which represents the graph of the given equation and we can see it is undefined at π/2
