Choose all which are correct. If tan theta = 3/4 and the terminal point determined by theta is in quadrant 3, then

cos theta = -4/5

csc theta = -5/3

cot theta = 4/3

sin theta = 3/5

Respuesta :

Since the terminus of [tex]\theta[/tex] lies in quadrant 3, we should have [tex]\cos\theta<0[/tex] and [tex]\sin\theta<0[/tex]. This eliminates the fourth option.

Recall that

[tex]\tan^2\theta+1=\sec^2\theta\implies\sec\theta=\pm\sqrt{\tan^2\theta+1}[/tex]

but we know that [tex]\cos\theta<0[/tex], which means [tex]\sec\theta<0[/tex], so we take the negative root above. Then

[tex]\sec\theta=-\sqrt{\left(\dfrac34\right)^2+1}=-\dfrac54\implies\cos\theta=-\dfrac45[/tex]

so the first option is correct.

We also know that

[tex]\cos^2\theta+\sin^2\theta=1\implies\sin\theta=\pm\sqrt{1-\cos^2\theta}[/tex]

and again we take the negative root here and find that

[tex]\sin\theta=-\sqrt{1-\left(-\dfrac45\right)^2}=-\dfrac35\implies\csc\theta=-\dfrac53[/tex]

so the second option is also correct.

Finally, we have

[tex]\cot\theta=\dfrac1{\tan\theta}=\dfrac43[/tex]

so the third option is also correct.

Answer:

cos theta = -4/5, csc theta = -5/3, cot theta = 4/3 is correct A, B, C

Step-by-step explanation:

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