# I don't understand curriculum 3.3

• ### Question

• so in lesson 3.3 we do this:

TextWindow.Write("Enter the angle in degrees and get the sine of the angle: ")
TextWindow.WriteLine("The sine of the angle is " + Math.Sin(number))
TextWindow.WriteLine("The arcsine value is " + Math.ArcSin(Math.Sin(number)))
TextWindow.WriteLine("The angle in degress is " + Math.GetDegrees(Math.ArcSin(Math.Sin(number))))
TextWindow.Write("Enter the angle in degrees and get the cosine of the angle: ")
TextWindow.WriteLine("The cosine of the angle is " + Math.Cos(number))

I guess my question is.... well I just dont understand how you get the sine of an angle without knowing the lengths of the right triangle?

because sine is the opposite side/hypotenuse right? so how do you find that out with just an angle?

Maybe my math is just so bad, but i really want to understand this.... ok thank you

• Edited by Sunday, December 15, 2013 12:59 AM
Sunday, December 15, 2013 12:58 AM

• No, the sides of a triangle are the hypotenuse, adjacent and opposite. the sine function is a trigonometric function of an angle. Not a measurement for a side of a triangle.

Hope this helps.

It is written: "'As surely as I live,' says the Lord, 'every knee will bow before me; every tongue will acknowledge God.'" Romans 14:11

Sunday, December 15, 2013 1:35 AM
• Curriculum 3.3 example is wrong.  You have to change the value degrees to radian.

* sin, cos, tan etc  requires radian value.

TextWindow.WriteLine("Enter the angle in degrees and get the sine of the angle:")
TextWindow.WriteLine("The sine of the angle is " + Math.Sin(number))
TextWindow.WriteLine("The arcsine of the angle is " + Math.ArcSin(Math.Sin(number)))
TextWindow.WriteLine("The angle in degrees is " + Math.GetDegrees(Math.ArcSin(Math.Sin(number))))
TextWindow.WriteLine("Enter the angle in degrees and get the cosine of the angle:")
TextWindow.WriteLine("The cosine of the angle is " + Math.Cos(number))

Sunday, December 15, 2013 2:21 AM

### All replies

• No, the sides of a triangle are the hypotenuse, adjacent and opposite. the sine function is a trigonometric function of an angle. Not a measurement for a side of a triangle.

Hope this helps.

It is written: "'As surely as I live,' says the Lord, 'every knee will bow before me; every tongue will acknowledge God.'" Romans 14:11

Sunday, December 15, 2013 1:35 AM
• Here is one use of sine:

```Ball = Shapes.AddEllipse(10,10)
While 1 = 1
Program.Delay(5)
Angle = Angle + 1
If Angle = 360 Then
Angle = 0
EndIf
x = Math.Cos(Math.GetRadians(Angle)) * 50 + 100
y = Math.Sin(Math.GetRadians(Angle)) * 50 + 100
Shapes.Move(Ball,x,y)
endWhile```

It is written: "'As surely as I live,' says the Lord, 'every knee will bow before me; every tongue will acknowledge God.'" Romans 14:11

Sunday, December 15, 2013 1:38 AM
• Curriculum 3.3 example is wrong.  You have to change the value degrees to radian.

* sin, cos, tan etc  requires radian value.

TextWindow.WriteLine("Enter the angle in degrees and get the sine of the angle:")