Question

if tan(2pi/3)sin(3pi/2-x)=1 what is cos(2x)?

Answer 1

well, try to simplify sin(3pi/2-x) first :)

Answer 2

and of course find the value of tan(2pi/3) first :)

Answer 3

Hi!! \(\huge\color{blue}{{Welcome~To~Open~Study}!!!!!!}\)

Answer 4

This?\[\text{if }\tan{\frac{2\pi}{3}}\sin{\frac{3\pi}{2-x}}=1\text{ what is}\cos{2x}\]

Answer 5

yes

Answer 6

Hm, alright then

Answer 7

@kittiwitti1 I believe that it is \(\displaystyle \sin\left(\frac{3\pi}2-x\right)\) instead

Answer 8

I think so too @kc_kennylau but that is why I asked :)

Answer 9

@kc_kennylau you're right sry!

Answer 10

xD

\[\text{Well, tangent is also equal to sine divided by cosine:}\tan{\theta}=\frac{\sin{\theta}}{\cos{\theta}}\]

Answer 11

...did everyone else leave ._.

Answer 12

@kittiwitti1 tnx

Answer 13

Lol...
Ok. We have two radian values, 2pi/3 and (3pi/2)-x\[\text{What do }\frac{2\pi}{3}\text{ and }\frac{3\pi}{2}\text{ equal in degrees?}\]

Answer 14

it means 2π/3=a° find a
what did you get? :)

Answer 15

*2pi/3 = a degrees, find a

Answer 16

http://prntscr.com/67ip8y

Yes you got it right :)

Answer 17

@kittiwitti1 2pi/3=120

Answer 18

^-^

Answer 19

So now can you solve with the degree values to find x? :)

Answer 20

@kittiwitti1 thanks

Answer 21

You're welcome~
but are you ok now or do you need more help :p

Answer 22

@kittiwitti1 i'm ok and i found the answer

Answer 23

Okay :)

Answer 24

Don't forget to close the question ^-^