I need confirmation on Trigonometry?

Question

So if x is more than 0 and less than 180...
the results of sin x will be two
while there will only be one result of cos and tan x
is it true?
thanks! and anyone has suggestion for further reading?

Answer 1

Are you talking about signs?

The easiest way I have found to determine the sign of a trigonometric number is by thinking about the unit circle - a circle with radius 1, centered on the origin. Imagine a radius of that circle, at a counterclockwise angle from the positive (right-hand) horizontal axis equal to your input. (If your input is negative, it describes a clockwise rotation.) Now, here's how you find each of the values.

* If you draw a vertical from the end of the radius to the horizontal axis, it will intersect the axis at a value equal to the horizontal component of the line. That value, positive or negative, is the -cosine- of the angle.

* If you draw a horizontal from the end of the radius to the vertical axis (which, I remind you, is positive upwards), it will intersect at a value equal to the vertical component. That value is the -sine-.

* If you measure the slope of the line, that is, the 'rise' (vertical) over the 'run' (horizontal), that is, the sine over the cosine, you will get the -tangent-.

I hope that helps.

Answer 2

Yes
when x is greater than 0 and less than 180 means x lies in the first and second quadrant and in the first quadrant all are positive while in the second quadrant only sin x is positive while cos x and tan x are negative.

Answer 3

I think you have the wrong idea =x

Any sinx when 0
Any cosx or tanx when 0

Answer 4

That is quite correct because
sin(180 -x ) = sin 180 cos x -cos 180sin x = sin x.
But cos(180 -x) = -cos x.
and tan(180 -x) = -tan x.

Answer 5

Huh?????
"the results of sin x will be two" simply cannot happen since |sin(x)| ≤ 1 for all x.

I have no idea **what** you're babbling about.. But, more importantly, I doubt that you do either.


Doug

Answer 6

if 0