2006-10-26 19:22:50 · 5 answers · asked by fdsfsjk k 3 in Science & Mathematics ➔ Mathematics
First thing to check - is your calculator on the right setting? If you're typing in degrees when your calculator is set to radians (or vice-versa), you'll be getting a wrong answer.
If that's all squared away, check the angles you're using. All of them should be between 0 and 180 degrees, or between 0 and pi radians. The sine function over this range is always positive, so you should always end up with a positive answer.
2006-10-26 19:43:30 · answer #1 · answered by J C 3 · 0⤊ 0⤋
Your calculator is either on the wrong setting or your not understanding properly.
If you draw the x and y real axes you will see that sin is only positive in the first and second quadrants ie: between 0 and 180.
when the angle becomes larger than this sin becomes negative. ie: in the third quadrant y/hyp = a negative value as in the fourth quadrant y/hyp is also a negative number. The hypotenues is always positive.
Sin(180-theta) in the third and fourth quadrant is equal to sin(-anglex) whicj is equal to -sin(anglex) because theta is more than 180 in these quadrants.
2006-10-26 20:53:22 · answer #2 · answered by Faz 4 · 0⤊ 0⤋
Perhaps the angle is greater than 90 and lesser than 180
Sin 90 = 1
Sin 120 = -(Sqrt3/2)
Sin 135 = -(1/sqrt2)
Sin 150 = -(1/2)
Sin 180 = 0
2006-10-28 01:33:56 · answer #3 · answered by Akilesh - Internet Undertaker 7 · 0⤊ 0⤋
the angle may be greater than 180
2006-10-26 19:27:19 · answer #4 · answered by ssshhh 3 · 0⤊ 0⤋
Uh, well, we can't see how you calculated it. First guess is the calculator is in the wrong degree/radian setting.
2006-10-26 19:27:06 · answer #5 · answered by topher8128 2 · 0⤊ 0⤋