Question

Given sin(−θ)=15 and tanθ=6√12 .

What is the value of cosθ ?

* √6/60

* 2√6/5

* −√6/60

* −2√6/5

Answer 1

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

Answer 2

Answer:

The answer is $-2\sqrt{6} /5$

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:

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

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

The answer is $-2\sqrt{6} /5$