Results 1 to 4 of 4

Math Help - Find the indicated trig function PLZ HELP!

  1. #1
    Newbie
    Joined
    Oct 2007
    Posts
    20

    Find the indicated trig function PLZ HELP!

    Find the indicated trig function of
    θ, if θ is an angle in standard position with the terminal side defined by the given

    point.
    (12, 16); Find cos
    θ.


    answer is 4 over 5 but how do i find this?

    please help :P
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Oct 2007
    From
    Nevada
    Posts
    188
    Quote Originally Posted by HelpMePleaseFriend View Post
    Find the indicated trig function of

    θ, if θ is an angle in standard position with the terminal side defined by the given

    point.
    (12, 16); Find cos θ.


    answer is 4 over 5 but how do i find this?

    please help :P
    (x,y) ---> (12,16) so 12 is your x value and 16 is your y value.

    Plot this point on a unit circle and connect the center to the point. The angle from the horizontal x axis to the line is θ.

    Have you ever learned SOHCAHTOA

    since you are dealing with cos, you want to know that cos is adjacent/hypothesis.

    In this instant, the hypothesis is the line you drew on the unit circle. To find it, we use the pathagorean theorem a^2 + b^2 = c^2.

    12^2 + 16^2 = 400

    take the square root to get c, which = 20

    now is when we look back to cos = adjacent / hypothesis

    the adjacent value is 16, while the hypothesis value is 20.

    16/20 is your answer, but when you simplify (both have multiples of 4 so divide both the numerator and denominator by this)

    AND AS YOU SAID...

    your answer will be 4/5
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Oct 2007
    Posts
    20

    so if...

    if the given numbers were lets say

    (14,18)

    i would do 14^2 = 196
    18^2 = 324
    = 520

    then sqaure root of 520 = 22.8 ? i'd round to 23?

    then fnd square root of 23 and 18

    square root of 23 comes to 4.795 would i round to 4.8 or 5

    square root of 18 = 4.24 so 4

    answer would be 5 over 4?

    nevermind that's wrong >_< i was doing square root. 23 is not divisable by anything >_< grrr i'm confused.

    i understand going through the first one... but no this one. i just gave 23 and 18 as an example but it doesn't seem possible to do?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie
    Joined
    Oct 2007
    Posts
    23
    if you have (14,18)
    then your hypotenuse will be ~22.80
    i don't recommend rounding down at this point.

    so your cos θ will be 18/22.80 ~ 0.789

    Note: when using trig functions, for cos θ & sin θ it is not possible for it to be greater than 1 unless you're using imaginary numbers which i doubt you're doing.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Find the indicated trig function HELP ^_^
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: September 5th 2013, 02:16 AM
  2. Replies: 1
    Last Post: October 23rd 2009, 04:38 AM
  3. Replies: 1
    Last Post: March 29th 2009, 10:07 PM
  4. find the requested trig function value of...
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: October 25th 2007, 07:38 PM
  5. Find the indicated trig function HELP ^_^
    Posted in the Trigonometry Forum
    Replies: 1
    Last Post: October 25th 2007, 07:33 PM

Search Tags


/mathhelpforum @mathhelpforum