Christos
  • Christos
WHERE IS MY MISTAKE?!?!? Problem: Given that sinƟ = 2/3 and Π/2 < Ɵ < Π find the exact value of cosƟ My solution: cos^2(Ɵ) + sin^2(Ɵ) = 1 sin^2(Ɵ) = 1 - cos^2(Ɵ) 4/9=1- cos^2(Ɵ) -5/9 = -cos^2(Ɵ) 5/9 = cos^2(Ɵ) cos(Ɵ) = -sqrt(5/9) Where is my mistake till now?
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
jamiebookeater
  • jamiebookeater
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
anonymous
  • anonymous
for one thing, the square root of 9 is 3
anonymous
  • anonymous
so if you were typing in an answer, it probably wanted it to look like \[\cos(\theta)=-\frac{\sqrt{5}}{3}\]
anonymous
  • anonymous
other than that, it is all correct

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

Christos
  • Christos
@satellite73 So I didnt make any mistakes at all?
geerky42
  • geerky42
No.
Christos
  • Christos
@satellite73 confirm to me please if all of my steps above were correct, and even if they had a mistake which line?
anonymous
  • anonymous
just draw a triangle and with 0 = 2 and h = 3.. then find a then do a/h to get cos theta
anonymous
  • anonymous
|dw:1362625931832:dw|
anonymous
  • anonymous
there is no mistake, although you should have \[\pm\sqrt{1-\left(\frac{2}{3}\right)^2}=\cos(\theta)\]
Christos
  • Christos
I should have used another fundamental identity?
anonymous
  • anonymous
or if you write \[\frac{5}{9}=\cos^2(\theta)\] then \[\pm\frac{\sqrt{5}}{3}=\cos(\theta)\] the reason you know it is negative is because you are in quadrant 2
Christos
  • Christos
got it its the same just modified, meeh
anonymous
  • anonymous
it is right, everything you did is right
Christos
  • Christos
I know why its negative yea
Christos
  • Christos
problem is that My solution is different from the one on the book
anonymous
  • anonymous
so there is no mistake here, although you should have a 3 in the denominator, rather than the square root of 9
anonymous
  • anonymous
what did the book get?
Christos
  • Christos
They the solutions might be equal but, I sill found a different solution
Christos
  • Christos
5/9
anonymous
  • anonymous
a different solution, or a different method
Christos
  • Christos
yea right..
anonymous
  • anonymous
nothing wrong with your method answer is \(-\frac{\sqrt{5}}{3}\) for sure
Christos
  • Christos
Books solution: 5/9
anonymous
  • anonymous
no that is \(\cos^2(\theta)\)
anonymous
  • anonymous
or else the book made a mistake it happens in any case you are right for sure, so don't fret about it
Christos
  • Christos
what do you mean "no that is cos2(θ)" ?
anonymous
  • anonymous
\[\cos(\theta)=-\frac{\sqrt{5}}{3}\] \[\cos^2(\theta)=\frac{5}{9}\]
Christos
  • Christos
hmmmmm
Christos
  • Christos
Is there any other method to approche the situation, like another identity to use for the specidif prob
Christos
  • Christos
I AM SORRY the answer in my book was: -sqrt(5)/3 !!!!!
anonymous
  • anonymous
|dw:1362626751880:dw|
Christos
  • Christos
So my final outcome is - sqrt(5)/sqrt3 HOW DO I PROCEED?
Christos
  • Christos
@satellite73
Christos
  • Christos
@Hero
Christos
  • Christos
@Mertsj
Christos
  • Christos
SOLVED THANK YOU ALL, SPECIAL THANKS TO SATELITE

Looking for something else?

Not the answer you are looking for? Search for more explanations.