## anonymous one year ago Please help! i will fan and medal! θ is in Quadrant III and cos^2(θ)=1/4 A. Evaluate cotθ. B. In two or more sentences, explain how to find the value of cotθ.

1. anonymous

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2. anonymous

3. anonymous

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4. anonymous

im sorry to say but MARIO

5. anonymous

Square root both the sides, after that you will get 2 values for cos theta, a positive and a negative value but you are given theta in in 3rd quadrant so use that fact to figure out the right value For reference: In 1st Quadrant all trig functions are positive In 2nd only sine and cosecant are positive In 3rd only tangent and cotangent are positive In 4th only cosine secant are positive A good mnemonic to remember is After School To College A for all postive S for sine and it's reciprocal positive T for tangent and it's reciprocal positive C for cosine and it's reciprocal positive

6. anonymous

okay so cos(θ)=1/2. how does that help me know what cotθ is? @Nishant_Garg

7. anonymous

Are you sure it's 1/2 and not -1/2?? Check carefully, After that if you remember your trig table the values of 30, 45, 60, 90 for your trig functions u should be able to find your angle and then use the same table to find cot theta Really it's more of a memory game here

8. anonymous

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9. anonymous

i dont know what trig table you are talking about @Nishant_Garg

10. anonymous

Basically trig values for the angles 30, 45, 60, 90 are somewhat basic and you should remember them for at least sine cos tan so really it's easy if u remember the values u can clearly tell which angle it is

11. anonymous

or u can use a calculator if u r allowed

12. princeharryyy

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13. anonymous

First tell me if you have figured out the correct equation $\cos(\theta)=\frac{1}{2}$ or $\cos(\theta)=-\frac{1}{2}$ Then I can guide you further

14. anonymous

$\cos (\theta)=-1/2$

15. anonymous

ok so now you can see how to modify the equation do you know at which angle cos will give 1/2?

16. anonymous

no i dont @Nishant_Garg

17. anonymous

ok so cos will give 1/2 at angle 60 degree or in radians pi/3 $\cos(\theta)=-\cos(60)$ Now here are some formulae's you should know $\cos(180+\theta)=\cos(180-\theta)=-\cos(\theta)$ Let's add and subtract 180 on the right side angle $\cos(\theta)=-\cos(60+180-180)$ You can modify it as $\cos(\theta)=-\cos(180-120)$ Now use the formula $\cos(180-\theta)=-\cos(\theta)$$\cos(\theta)=-(-\cos(120))=\cos(120)$

18. anonymous

I actually got a friend to help me. thank you so much for the help! @Nishant_Garg

19. anonymous

Ah, you're welcome!