The angle \theta_1θ
1

theta, start subscript, 1, end subscript is located in Quadrant \text{III}IIIstart text, I, I, I, end text, and \cos(\theta_1)=-\dfrac{13}{30}cos(θ
1

)=−
30
13

cosine, left parenthesis, theta, start subscript, 1, end subscript, right parenthesis, equals, minus, start fraction, 13, divided by, 30, end fraction .
What is the value of \sin(\theta_1)sin(θ
1

)sine, left parenthesis, theta, start subscript, 1, end subscript, right parenthesis?
Express your answer exactly.

Respuesta :

Answer:

sin ( θ ) = 3√21 / 17

Step-by-step explanation:

Given:-

- The angle (θ) lies in the first quadrant. Where theta is defined as:

                              cos ( θ ) = 10 / 17

Find:-

- Find sin ( θ ) :

Solution:-

- We will draw a right angle triangle in the first quadrant. With base, B = 10 and hypotenuse H = 17. Since,

                              cos ( θ ) = B / H = 10 / 17

- Using pythagorean theorem determine the perpendicular side length:

                              H^2 - B^2 = P^2

                              17^2 - 10^2 = P^2

                              √189 = P

                             P = 3√21

- Now evaluate sin ( θ ):

                              sin ( θ ) = P / H

                              sin ( θ ) = 3√21 / 17

The value will be  [tex]sin\theta_{1} =-\dfrac{\sqrt{731} }{\rm 30}[/tex].

Given,

[tex]\rm cos\rm \theta_{1} =-\dfrac{13}{30}[/tex].

And [tex]\theta_{1}[/tex] lies in the third quadrant.

We know that,

[tex]\rm cos\theta=\dfrac{\rm base}{\rm hypotenuse}[/tex]

Since,  [tex]\rm cos\rm \theta_{1} =-\dfrac{13}{30}[/tex]

Here, [tex]\rm base=13[/tex] and [tex]\rm hypotenuse=30[/tex].

Now, applying Pythagoras theorem, we get

[tex]\rm hypotenuse^{2} =\rm perpendicular^{2} +\rm Base^{2}[/tex]

[tex]30^{2} =\rm perpendicular^{2} +13^{2}[/tex]

[tex]900 =\rm perpendicular^{2} +169[/tex]

[tex]731 =\rm perpendicular^{2}[/tex]

[tex]\rm perpendicular=\sqrt{731}[/tex]

Hence,

[tex]sin\theta_{1} =\dfrac{\rm perpendicular}{\rm hypotenuse}[/tex]

[tex]sin\theta_{1} =\dfrac{\sqrt{731} }{\rm 30}[/tex]

Since [tex]\theta_{1}[/tex] lies in the third quadrant, so

[tex]sin\theta_{1} =-\dfrac{\sqrt{731} }{\rm 30}[/tex]

Hence, the value of [tex]sin\theta_{1}[/tex] is [tex]-\dfrac{\sqrt{731} }{\rm 30}[/tex] .

For more details on trigonometric ratio follow the link:

https://brainly.com/question/1201366