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Mathematics 21 Online
OpenStudy (anonymous):

how do I find the exact value of the expression cos60 + tan60

jigglypuff314 (jigglypuff314):

cos = adj over hyp tan = opp over adj |dw:1417396828750:dw|

OpenStudy (anonymous):

WELL, I don't want to do the tan(a+b) rule, and I don't remember it, so cos60 + tan60 = =cos60 + sin60/cos(60) =cos^2 60/cos(60) + sin60/cos(60) ={ cos^2 60 + cos(60) }/cos(60) (draw a 30-60-90 triangle, you will know that:) sin(60)=sqrt3 /2 cos(60)=1 /2 (therefore) cos^2(60)=1/4 ={ 1/4 + 1/2 }/ (sqrt3/2) ={ 1/4 + 2/4 }/ (sqrt3/2) ={ 3/4 }/ (sqrt3/2) ={ 3/2 }/ (sqrt3) = 3 / { 2 sqrt3 }

OpenStudy (anonymous):

don't know why I did all that, but I like playing.

jigglypuff314 (jigglypuff314):

omg @WHAT?! you just confused the heck out of me xD

OpenStudy (anonymous):

my 3rd line is supposed to be cos^2(60)+sin(60) on top of the fracion.

OpenStudy (anonymous):

I did everything after that right though.

OpenStudy (anonymous):

no I did not.

OpenStudy (jhannybean):

One method looks like it's done geometrically, another arithmetically

OpenStudy (anonymous):

just ignore me... and I know my mistake so no need rebuking me over it so much. you certainly can.

OpenStudy (anonymous):

Here's the fixed version of WHAT?!'s method: \[\cos(60)+\tan(60)=\cos(60)+\frac{\sin(60)}{\cos(60)} = \frac{\cos^2(60)+\sin(60)}{\cos(60)}=\frac{0.25+ \frac{\sqrt{3}}{2}}{0.5}\] \[0.5+\sqrt{3}\]

OpenStudy (anonymous):

tom why does cos60 plus tan 60 equal cos60 plus sin60/cos60

OpenStudy (jhannybean):

Think about it: \[60^\circ = \frac{\pi}{3}\]\[\cos\left(\frac{\pi}{3}\right)= ~?\]\[\tan\left(\frac{\pi}{3}\right)=~?\]

OpenStudy (anonymous):

where is the sine coming from?

OpenStudy (anonymous):

I am not supposed to use a calculator

OpenStudy (jhannybean):

no calculator needed.

jigglypuff314 (jigglypuff314):

tan = sin over cos

OpenStudy (anonymous):

\[\cos(60)+\tan(60)=\frac{\cos^2(60)}{\cos(60)}+\frac{\sin(60)}{\cos(60)}=\frac{\cos^2(60)+\sin(60)}{\cos(60)}\]

OpenStudy (anonymous):

what I am so confused

OpenStudy (anonymous):

You want a common denominator @Benghazi, so we change cos(60) into cos^2(60)/cos(60) then we can combine the two fractions.

OpenStudy (anonymous):

I understand the need for a common denominator but wouldn't you have to do something like cancellation or distribution or something like that. What you do on one side you do to the other.

OpenStudy (anonymous):

tan equal sine over cosine is that correct?

OpenStudy (freckles):

if that confused you just find cos(60) and tan(60) then add those results

jigglypuff314 (jigglypuff314):

^

OpenStudy (freckles):

|dw:1417397756255:dw| i like jiggly's drawing

OpenStudy (freckles):

and you should love it too because it can help you find cos(60) and tan(60)

OpenStudy (anonymous):

freckles explain to me How I would use it. Like I literally do not know how

OpenStudy (freckles):

cos(60)=adj side to the angle with measure 60/hyp

OpenStudy (jhannybean):

\[\cos\left(\frac{\pi}{3}\right) = \frac{1}{2}\]\[\tan\left(\frac{\pi}{3}\right) = \frac{\sqrt{3}}{2} \cdot \frac{2}{1} = \sqrt{3}\]\[\cos(60)+\tan(60) = \cos\left(\frac{\pi}{3}\right)+\tan\left(\frac{\pi}{3}\right) = \frac{1}{2}+\sqrt{3}\]

OpenStudy (freckles):

tan(60)=opp side to the angle with measure 60/adj side to the angle with measure 60

OpenStudy (jhannybean):

I think once you know your unit circle triangles are really unnecessary. And there really is no arithmetic process needed.

OpenStudy (anonymous):

Do you guys mind if we follow toms example cuz i think I understand better from that

OpenStudy (freckles):

|dw:1417397918843:dw| and of course the hyp no matter angle we are labeling the triangle with respect to is the side opp to the 90 deg angle

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