Sin (-x)=??? is it -cos x??

Answer 1

Since cosine is symmetric with the Y axis -
cos(x) = cos(-x)
Since sine is symmetric with to the origin -
sin(x) = -sin(-x)

since sin(-x) = -sin(x) it cannot equal -cos(x)

Answer 2

Indeed, agree I do. sin (-x) = -sin x.
Now here's why:

sin x = opposite / hypotenuse
cos x = adjacent / hypotenuse

A negative can't convert one to the other. Now that we have established that let's look at why sin (-x) = -sin x. If you have a certain angle (let's say pi/4 radians) that will give a certain ratio of the opposite side to the hypotenuse. If the angle is the same this ratio is the same. A negative doesn't change this ratio - it only changes which way you are measuring the angle on the unit circle. Okeydoke?

Hope this helps!

Answer 3

yep, -sin(x)

if you wanted more,
cos(-x) = cos(x),
sine has the negative move out because it is an odd function, while cosine has the negative dissapear (it actually reflects on itself) and is known as an even funciton.

Answer 4

If you look at a graph of sin(x), you will see that sin(-x) = -sin(x).
For example sin(-30 degrees) = -0.5, and
sin(30 degrees) = +0.5.

Answer 5

No.

sin(-x) = -sin x

Answer 6

sin (-x) = -sin (x)

Answer 7

no, it's -sinx