Ok so this chapter is a little confusing for me. I kinda understand the trig chart but i think thats why im confused or it can be because of working and solving the formulas. I dont really understand like how to solve formulas for all the things we have learned but i do know the formulas. The formulas i understand and know is the double and half angle formulas. There is db and half angle formulas for sin, cos, and tan.
Double angle formulas for sin2(a):
2sin(a)cos(a)
Half angle formulas for sin(a/2):
+/- square root of (1-cos(a)/2)
Double angle formulas for cos2a:
cos^2a-sin^2a, 1-2sin^2a, 2cos^2a-1
Half angle formulas for cosa/2:
+/- square root 1+cosa/2
Double angle formulas for tan2a:
2tana/1-tan^2a
Half angle formulas for tana/2:
+/- square root of 1-cosa/1+cosa, sina/1+cosa, 1-cosa/sina
Those are the formulas for db and half angles for sin, cos, and tan. the thing i dont understand is solving them in a problem.
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All you have to do is look for something that resembles them in a problem. They can differ somewhat, but you have to make them balanced. Then plug in the info you have and then solve.
ReplyDeletewhen given any equation on a quiz or a test you must look at the given information and recognize how it relates to something else that will help you solve. Working these problems is no different. On a quiz or test you will be given the answer and you"ll have to find the equation or you can be given part of the equation and by recognizing the formula necessary you can solve the rest of the problem. a third option would be a test or quiz where the entire formula is given this is when you would have to plug in. the only way you can plug in is for the parts of the equation where it says sin(*) or Cos(*) or tan(*)
ReplyDeleteplugging in for the double and half formulas is no different than plugging in for the other equations you have.
just have your trig chart memorized and when the equation has something that applies to plugging in, do so
for example if your equation has sin (90) re write the equation and where the equation has sin (90) just put 1.
To solve them all you do is look at the formulas, you find which one is the right one to use in the problem, and you plug in the number from the equation, then solve.
ReplyDeleteYou use double or half angle formulas when you are asked for a decimal. Try to balance out both sides of a problem and solve. I just need to memorize these formulas now. I can't memorize information to save my life...
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