Find the indicated trig function of
θ, if θ is an angle in standard position with the terminal side defined by the given
(12, 16); Find cos θ.
answer is 4 over 5 but how do i find this?
please help :P
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
if the given numbers were lets say
i would do 14^2 = 196
18^2 = 324
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?
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.