Question

if sinx = 4/5 and x is in the first quadrant, find sin2x
What I know :
sin2x = 2sinxcosx (in my notes)
cos2x = 1-2sin^2x = -7/25 (I solved that myself)
sinx = 4/5 (given)

Answer 1

Ok we now sin^2(x)+cos^2(x)=1 replace for sin(x) and find cos(x) then find sin(2x)

Answer 2

My notes are telling me to use the unit circle and to use the terminal point

Answer 3

Bro thats straight forward you got 16/25 +cos^2(x)=1 then cos^2(x)=9/25 then cos(x)=3/5 therfore sin(2x)=2(3/5)(4/5)=24/25 thats it i gave you the answer

Answer 4

I'm a girl, not a "bro" and obviously it's not straight forward to me since I'm asking for help . I don't understand the terminal points and I'm taking an algebra 2 class and it's apparently trigonometry is apart of algebra 2

Answer 5

Sorry i had no idea what sex are you since your username didn't signify anything well yeah thats trig and it seems that you wrote in your notes everything that i just used what is the problem?

Answer 6

They're my initials and I don't understand how to find a terminal point . I don't understand trigonometry whatsoever

Answer 7

How old are you?

Answer 8

17

Answer 9

I don't see why my age is relevant lol

Answer 10

Nothing its just that I've taken trig form when i was 14 😂😜 im 17 now

Answer 11

If you want me I can explain trig to you but it would take time

Answer 12

how do you understand this

Answer 13

What trig?

Answer 14

yeah lol

Answer 15

By using scalar product in the trig circle

Answer 16

what's scalar product

Answer 17

Product of vectors, havent you heard of it?

Answer 18

no ..

Answer 19

Have you heard about the trig circle?

Answer 20

is that unit circle ?

Answer 21

?