Question

If the point (x, √3/3) is on the unit circle, what
is x?

A) 2\3
B) √6\3
C) 4/9
D) √2\3

Answer 1

use the pythag thrm to develop:

x = sqrt(1-y^2)

Answer 2

in other words: x^2 + y^2 = 1, and we know y

Answer 3

So is it D?

Answer 4

show me the math you did to get to D

Answer 5

or, show me if:

(sqrt(2)/3)^2 + (sqrt(3)/3)^2 = 1

Answer 6

Okay, hold on a moment, please.

Answer 7

I just plugged (sqrt(2)/3)^2 + (sqrt(3)/3)^2 = 1 into my calculator and it came out as false.

Answer 8

D looks off, but it has some trick about it

√(2\3) is correct, but i believe D is written as: √(2)\3 which is a different number

Answer 9

\[x=\sqrt{1-\left(\frac{\sqrt{3}}{3}\right)^2}\]
\[x=\sqrt{1-\frac39}\]
\[x=\sqrt{\frac99-\frac39}\]
\[x=\sqrt{\frac69}\]
\[x=\sqrt{\frac23}~or~x=\frac{\sqrt 6}{3}\]

Answer 10

so im not sure how your process took you. but if you got to sqrt(2/3) it right, but just not an option. in many cases, they dont like a sqrt on the bottom. so sqrt(6)/3 is 'more accurate'.

Answer 11

Ohhhhh. I see, I think I messed up after the 3rd step! Thank you!

Do you mind helping me with a few more problems? I really would appropriate it.

Answer 12

i have ot be leaving soon, so i dont know if i have the time, but whatcha got?

Answer 13

What is the period of the cosine and sine functions?

Pi
2pi
4pi
cosine and sine are not periodic

I believe it's 2pi, I think I've had this problem before...but I'm not quite sure.

Answer 14

cos(0) = cos(2pi)
sin(0) = sin(2pi)

so yes, they are periodic (they repeat themselves) at 2pi

Answer 15

Thanks, okay. I have a few more...hold on a sec, please.

Answer 16

Use a calculator to evaluate cot π\5.

0.561
1.376
91.185
32.142

Answer 17

lolmy guess was right

Answer 18

i know pi/4 has a tangent of 1, pi/5 is less than 1 by a smidgen; so id say cot has to be bigger than 1 by a smidgen ...

http://www.wolframalpha.com/input/?i=cot%28pi%2F5%29

Answer 19

I also got 1.376.

Answer 20

my times up .... good luck with these. you seem to be doing fine so far.

Answer 21

Thank you!