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Random math problem

Discussion in 'Off Topic [BG]' started by Figjam, Apr 1, 2005.


  1. Figjam

    Figjam

    Aug 5, 2003
    Boston, MA
    if f(x) = a sin (bx) , what is the maximum value in the range?

    (1) a
    (2) b
    (3) a+ b
    (4) there is no maximum


    eh? also

    Evaluate: sin( arc cos radical2/2)

    (1)1
    (2) radical 2 / 2
    (3) radical 3/2
    (4) radical 2
     
  2. Against Will

    Against Will Supporting Member

    Dec 10, 2003
    Big Sound Central
    Trig for me was like getting hit with a bigrig. You dig, fig?
     
  3. DigMe

    DigMe

    Aug 10, 2002
    Waco, TX
    Don't ask me I just work at a school.

    brad cook
     
  4. Figjam

    Figjam

    Aug 5, 2003
    Boston, MA
    Heh , i used to know how to do this stuff but its been a little and my assignment is kinda cumulative and i forget a lot.
     
  5. Figjam

    Figjam

    Aug 5, 2003
    Boston, MA
    brother just explained to me that 'arc' means inverse, so then that problem simplifies into sin(45). And we think the answer to the first one is 'no max' but any help would be...helpful.
     
  6. Brad Barker

    Brad Barker Supporting Member

    Apr 13, 2001
    berkeley, ca

    1. (1)

    "a" is the amplitude of the sine wave. the function varies from -a to a.

    that "b" just adjusts the period--makes it shorter or longer of a wave. has nothing to do with the maximum or minimum values of the function.

    there's a way of solving that problem, more like checking your common sense, with calculus, but i'm guessing this is a precal class?

    2. draw a triangle. the angle is arc cos (sqrt(2)/2).

    so that means the adjacent side is sqrt(2) and the hypoteneuse is 2. use the pythogorean theorem to find the opposite side of the triangle.

    then the sine of that angle is just opposite over hypoteneuse.

    you can do that your self! :spit:



    in other news, i just found out i got a 99/100 on my differential equations test. the point i missed was because i said that 3/8 - 1/4 = 1/4.

    :oops:

    variation of parameters? no problem! arithemetic? watch out!
     
  7. Figjam

    Figjam

    Aug 5, 2003
    Boston, MA
    thanks, bro explained to me the second one but first one im silly, i sohulda known that. thanks/
     
  8. Brad Barker

    Brad Barker Supporting Member

    Apr 13, 2001
    berkeley, ca
    there most certainly IS a maximum!

    just graph the thing!

    is there a value of y that this function cannot get bigger than, for every value of x in its domain?

    there damn sure is.

    the sine function will reach its maximum when x = pi/2 + 2 n pi, where n is some integer.


    and that second problem, the "draw a representative triangle" method is VERY helpful. it rears its head again in calc 2 at some point, too.
     
  9. Figjam

    Figjam

    Aug 5, 2003
    Boston, MA
    Yeah i was being silly. Silly goose me.

    Im taking calc 2 next year (took trig and precalc this year) so illl probably be making math threads often when im confused!
     
  10. Brad Barker

    Brad Barker Supporting Member

    Apr 13, 2001
    berkeley, ca
    there's always www.physicsforums.com for that stuff. plus, you could ask them to do your science homework, too! :p
     
  11. Figjam

    Figjam

    Aug 5, 2003
    Boston, MA
    I'll take a look, thanks.
     
  12. "splunge"
     
  13. Brad Barker

    Brad Barker Supporting Member

    Apr 13, 2001
    berkeley, ca
    :confused: