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cos and sin values in projectile motion
- Thread starter orthoboy
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I basically memorized them from doing unit circle stuff in Trig and using them so much.
You can always draw a triangle I guess if you're unsure.
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I just memorized them. They follow the same pattern though - the values for sin going from 0-90 degrees is opposite of the values for cos going 0-90. If you can remember one, you can figure out the other. I find it's also helpful to memorize the decimal values and know what sqrt(2) and sqrt(3) equals.
Maybe it's easier to visualize a graph? A sin graph starts at zero while a cos graph starts at 1. That means that sin(0)=sqrt(0)/2=0 and cos(0)=sqrt(4)/2=1. Then the numbers under the sqrt just go 0, 1, 2, 3, 4 as you go from 0 to 90 degrees for sin and 4, 3, 2, 1, 0 for cos. They're always over 2.
Maybe it's easier to visualize a graph? A sin graph starts at zero while a cos graph starts at 1. That means that sin(0)=sqrt(0)/2=0 and cos(0)=sqrt(4)/2=1. Then the numbers under the sqrt just go 0, 1, 2, 3, 4 as you go from 0 to 90 degrees for sin and 4, 3, 2, 1, 0 for cos. They're always over 2.
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It's pretty simple to memorize them, and the order of the values is just opposite for cos than it is for sin. That's just five simple values to remember, should just be a minute or so of memorization work.
yeah just gotta memorize them. I only memorize the 30 degree value, then i know in what order its gonna go. Also, with enought practice it becomes quite second nature. like at 30 degress you know that the cos value should be larger than sin, cuz well 30 is closer to x=1, then y=1. Therefore, i know its approximately aroun .9 for cos and 1/2 for sin.
