Ask your own question, for FREE!
Mathematics 9 Online
OpenStudy (kkbrookly):

Will give medal and fan!

OpenStudy (kkbrookly):

Given tan theta=-sqrt2/2 and theta lies in quadrant IV, find cos theta/2

OpenStudy (kkbrookly):

@SyedMohammed98 @TheSmartOne

OpenStudy (kkbrookly):

@mady111

OpenStudy (anonymous):

yes!

OpenStudy (kkbrookly):

You can help me?

OpenStudy (anonymous):

i can

OpenStudy (kkbrookly):

Sweet. What do I need to do first?

OpenStudy (anonymous):

hold on

OpenStudy (anonymous):

\[\sin \theta \sqrt{2/2}\]

OpenStudy (anonymous):

\[\cos \theta=-\sqrt{2/2}\]

OpenStudy (anonymous):

- in the first on to

OpenStudy (anonymous):

\[\tan \theta=1 \cot=1 \csc -\sqrt{2} \sec =-\sqrt{2}\]

OpenStudy (anonymous):

since the angle formed in quadrant III is 90 degrees, then if we bisect that angle we'll get half of that which is 45 degrees.... so we know that in a right triangle with 45 degrees, the sides will have a ratio of 1:1:square root of 2 so let's suppose our hypotenuse is sqrt of 2 and the legs have measure of 1. Since we're in quadrant 3 both legs will have measure of -, (because at quadrant 3, x and y are both negative) 1 but the hypotenuse will still be sqrt2... so we'll have using this info, you can now compute for the 6 trig. functions of theta.. so sin theta=-1/sqrt2=-sqrt(2)/2 cos theta=-1/sqrt2=-sqrt(2)/2 tan theta=sin theta/cos theta <a trigonometric identity since sin theta=cos theta in this case, tan theta=1 cot theta=1/tan theta=1/1=1 sec theta= 1/cos theta=1/(-1/sqrt2)=-sqrt2 csc theta=1/sin theta=1/(-1/sqrt2)=-sqrt2

OpenStudy (kkbrookly):

So I use cos theta=-1/sqrt2=-sqrt(2)/2

OpenStudy (anonymous):

yes you got it

OpenStudy (kkbrookly):

Do I have to plug in anything for tan?

OpenStudy (kkbrookly):

Or I just put that equation in the calculator?

OpenStudy (anonymous):

no put that in the calculator

OpenStudy (anonymous):

did you get the answer you was looking for

OpenStudy (kkbrookly):

I put it into wolfram because I don't have a graphing calculator and the answer was exactly what I put in

OpenStudy (anonymous):

hmm ill do it a different way for you

OpenStudy (kkbrookly):

Alright

OpenStudy (anonymous):

The six trig functions are listed below @ stands for theta. x,y, and r are in reference to the trig functions related to a unit circle. Cos@ = adj/hyp or x/r....Sec@ = hyp/adj or r/x Sin@ = opp/hyp.or y/r..Csc@ = hyp/opp or r/y Tan@ = opp/adj or y/x...Cot@ = adj/opp or x/y Since your angle is QIV, Xs are positive, Ys are negative This means that your Sine, Cosecant, Tangent, and Cotangent are going to be negative. With that said... The sec@ = Sqrt(3)/1 remember any number can be written as a ratio by putting it over a 1. This is the key. x = 1 and r = sqrt(3). Using the Pythagorean theorem since we form a right triangle in drawing the coordinate system and @ in the 4th Quad, we get...that x = 1, r = sqrt(3) and y is all we need to find. (1)^2 + y^2 = (sqrt3)^2 y = sqrt(2) Now you have adj or x = 1, opp or y = sqrt(2), and hyp or r = sqrt(3) Write your functions and remember which ones are negative. Sin@ = y/r = sqrt2/sqrt3 = sqrt6/3 (negative) Cos@ = x/r = 1/sqrt3 = sqrt3/3 (positive) Tan@ = sqrt2/1 = sqrt 2 (negative) Csc@ = r/y = sqrt3/sqrt2 = sqrt6/2 (negative) Cot@ = x/y = 1/sqrt2 = sqrt2/2 (negative

OpenStudy (anonymous):

is this any better?

OpenStudy (kkbrookly):

I'm sorry. I'm still confused. I'm not sure what to do next.

OpenStudy (anonymous):

okay ill draw it out for you

OpenStudy (kkbrookly):

Okay thank you

OpenStudy (anonymous):

|dw:1430167828760:dw|

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!