The Sine of -3x, Looks like this Sin(-3x).?

Question

The Sine of -3x, Looks like this Sin(-3x). When I put it in my calculator, it gives me a reflection over the x axis. So does -sinx = Sin(-x) ???

Answer 1

Figure it out. The definition of Sine is "the ratio of the opposite side to the hypotenuse" for a given angle. A negative number for the angle would simply mean that it points down rather than up (bottom right quadrant, rather than top right). So both the opposite side and the hypotenuse would keep their same absolute lengths, and their ratio would be the same.