PRECALC WHIZ HELP! PLEASE pleaseee

Question

anonymous · Answer

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anonymous · Answer

hmm im trying and im getting fidning no answer ...

anonymous · Answer

did you try no answer?

anonymous · Answer

i dont think i can do that option though for that one, maybe you can help me with this one then/??---

accessdenied · Answer

Have you tried factoring it like a normal quadratic equation?

anonymous · Answer

ya for the one cos(theta) is equal to sqrt(8)/3 and cos(2theta) is 2sqrt(8)/3

campbell_st · Answer

its a quadratic that needs to be solves

(2sin(x) -1)(sin(x) -2) = 0

then sin(x) = 1/2, 2 

sin(x) = 2 is undefined so ignore it

now find sin(x) = 1/2                x = pi/6 or 30

anonymous · Answer

invn177 so whats the scos (2theta)?  you think i just wrote it wrong

anonymous · Answer

so campbell is the answer just simply pi/6 or is it another form of that too since it goes around it twice?

campbell_st · Answer

in this question draw a triangle hypotenuse 3 and opposite side 1

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use pythagoras to find the length of the opposite side

$$?^2 = 3^2 - 1^2$$

the adjacent side is $$\sqrt{8}$$

so $$\cos(\theta) = \sqrt{8}/3$$

campbell_st · Answer

since the domain is 0 to 2pi.... then there is an angle in the 2nd quadrant... as you answer is positive

sin is positive in1st and second quadrants 


so its   pi - pi/6  = 5pi/6 

answers  pi/6 and 5pi/6

anonymous · Answer

THANKS YOUR BEST can u explain the second part of the other question the cos(2theta) now