1. The problem is about understanding how to count angles when dealing with transformations of the sine function, specifically for the function $-2\sin x$ and counting from $270^\circ$ (often called $C270$). 2. The sine function $\sin x$ is periodic with period $360^\circ$, and angles are usually measured starting from $0^\circ$ on the unit circle, moving counterclockwise. 3. When you have a transformation like $-2\sin x$, the negative sign reflects the sine wave across the x-axis, and the amplitude is scaled by 2. 4. Counting from $270^\circ$ means you start measuring angles at the point on the unit circle corresponding to $270^\circ$, which is the bottom of the circle (where sine is $-1$). 5. So, if the question is whether to start counting from zero or from where the "door" (likely meaning the reference angle or starting point) is, the answer is: you start counting angles from the reference point given, which in this case is $270^\circ$. 6. This means you treat $270^\circ$ as your zero point for counting angles in this transformed sine function context. 7. To summarize: for transformations and counting angles from $C270$, you start counting from $270^\circ$, not from zero. Final answer: When counting from $C270$, start counting angles from $270^\circ$, the given reference point, not from zero.