Monday, December 7, 2009

Stephen's Reflection

Ok so this week we learned about trig functions. I think the easiest thing to talk about is figuring out which quadrants they are in. Things to remember about trig functions are that sin is positive in quadrant 1 and 2 which is y, cosine is positive in 1 and 4 which is x, and tangent is positive in 1 and 3 which is both + x/y and -x, -y.

Ex: find the values of x between 0 greater than or equal to x greater than or equal to 360 for sinx=.6

you first have to solve for x so you take the inverse of sin on both sides which is sin^-1 so it will look like x=sin^-1(.6)
then you solve sin^-1(.6) which = 36.870. That is in the first quadrant so that is the first answer out of 2.
To move to quadrant two to find the 2nd answer, you make it negative and add 180.
180-36.870=143.130 and that is your second answer.

I understand most of this section but there is one thing i could use help on. When turning a trig function into another, i always do the more complicated for some reason. I dont know if there is an easier way to do it so i use the one im most certain of. So i need advice with that if you know how to give it. And another question, will i always get the same answer as the easier way if i do it the harder way cause that always worries me.
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3 comments:

  1. TERRIODecember 8, 2009 at 5:55 PM

    I'm not really sure with what your asking but I'm sure that if there are two ways to do something and you do it right both ways then you should come out with the same answer.

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  2. AnonymousDecember 9, 2009 at 8:23 AM

    My best advice to your problem is to just think of all the identites and how they will work out before you use them. to explain: if you know that there are two identities that will work then think of what the steps to follow would involve before you choose which one you will use.

    To answer your second question, yes if there is more than one way and you just choose the harder way then all is well it may cost you more time on the tests and exams but you should still get the same answer as long as you know the harder way is a possible correct way

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  3. alainaDecember 9, 2009 at 11:01 PM

    KNOW.YOUR.IDENTITIES. :)
    if most of the 'numbers' in the problem are in terms of sin or cos, change the ones that aren't to match the ones that are. (this works with sec and csc, too).
    *tan=sin/cos
    *cot=1/tan OR cos/sin
    Even if there are two ways to do one problem, either way should give you the same answer.

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