Respuesta :

amosarteta

Answer:

B). −2√6/5

Step-by-step explanation:

tan theta = sin theta/ cos theta

Multiply each side by cos theta

tan theta * cos theta = sin theta

Divide each side by tan theta

cos theta = sin theta/ tan theta

We know that the sin (- theta) = - sin theta  since sin is and odd function

sin theta  = - (  sin (-theta))

Putting this into the above equation,

cos theta =  - (  sin (-theta)) / tan theta

cos theta = - 1/5 / (sqrt(6)/12)

Remember when dividing fractions, we use copy dot flip

cos theta =   -1/5  * 12/ sqrt(6)

cos theta = -12/ (5 sqrt(6))

We cannot leave a sqrt in the denominator, so multiply the top and bottom by sqrt(6)/sqrt(6)

cos theta = -12/ (5 sqrt(6))  * sqrt(6)/sqrt(6)

cos theta = -12 sqrt(6) / 5*6

Simplify the fraction.

cos theta = -2 sqrt(60/5

HOPE IT HELPS:D BRAINLIEST PLZ:D

erolkayacan

Answer:

The answer is [tex]-2\sqrt{6} /5[/tex]

Step-by-step explanation:

We can write tangent function as a division of sinus and cosinus function as following:

tan(x)=sin(x)/cos(x)

Sinus is an odd function. Therefore,

sin(-θ)=-sin(θ)

So, it makes sin(θ)=-1/5

tan(θ)=sin(θ)/cos(θ)

If we put correct values instead of functions and leave cosinus alone it will be as following:

[tex]\sqrt{6}/12=-1/5*cos(fi)\\ Cos(fi)=-12/5\sqrt{6}[/tex]

[tex]cos(fi)=-12\sqrt{6}/30\\cos(fi)=-2\sqrt{6} /5[/tex]

The answer is [tex]-2\sqrt{6} /5[/tex]

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