Question

Please help with the attached Precalc/Trig problem :(

Answer 1

you must love trig, because I like helping with trig and calc more than anything.

Answer 2

Yay! So you can help?

Answer 3

yes

Answer 4

go to this web site http://answers.yahoo.com/question/index?qid=20110214192448AAap04i

Answer 5

did the web page come up for you??

Answer 6

Yes, it worked

Answer 7

see the problem and the answer laid out.

Answer 8

Yes, but I'm having trouble with the steps of this problem :/ Do I just follow or can you teach me?

Answer 9

give a few min let me see if I can teach on this board someway.

Answer 10

Thanks!

Answer 11

3sin^2X+2sinx=1 this is the quadtract form so we can move the across the equals and set this equal to zero like this 3sin^2X+2sinX-1=0

Answer 12

Oh I see

Answer 13

so when we use the quad form which is A^2+b^2 =c^2 know this form right?

Answer 14

I'm familiar with it, yes

Answer 15

do it like this
Solve this using the quadratic formula.

y = [2 +/- sqrt(4 - 4(3)(-1))]/[2*3]
y = [2 +/- sqrt(4 + 12)]/6
y = [2 +/- sqrt(16)]/6
y = [2 +/- 4]/6
y = [1 +/- 2]/3
y = { [1 + 2]/3 , [1 - 2]/3 }
y = { 1, -1/3 }

Answer 16

Ok, got it. So y=1,-1/3

Answer 17

yes very good

Answer 18

now the next step is here:
Now, make y = sin(x) (back-substitute)

sin(x) = { 1, -1/3 }

So now, we have two equations to solve: sin(x) = 1, and sin(x) = -1/3.
Now, sin(x) = 1 does not have a solution within 270 and 360 degrees (the solution would be x = 90 degrees, 450 degrees, -270 degrees, etc).

But if sin(x) = -1/3, then
x = arcsin(-1/3) (Note: the range of arcsin is between -90 and 90 degrees, so it would return a value between -90 degrees and 0 degrees. For that reason, you have to add 360 degrees).

x = arcsin(-1/3) + 360

If you want an approximation, plug in arcsin(-1/3) into your calculator (remember to put it in DEG mode!).

x = -19.471220634490691369245999339962 + 360
x = 340.52877936550930863075400066004

Answer 19

it is really hard to do this problem without a calculator

Answer 20

Whoa, thanks. Hmm, your explanation makes sense. Thanks very much for helping me!

Answer 21

sorry I could not break down further, but like you see it is not easy to do

Answer 22

Yes, you are right. I'm sure I'll get better after practice.

Answer 23

So just to confirm, final answer is b.

Answer 24

yes I start college my self on Sept 24 taking Trig and than I leave for Texas on Jan 14th to major in Physics engineering

Answer 25

final answer is b.

Answer 26

Wow, that's really exciting! Good luck on your future! You'll go far

Answer 27

thanks if you don't mind answering are you high school or college?

Answer 28

no biggie if you don't want to tell me. I understand why

Answer 29

Oh it's fine! I'm a high schooler. Still haha last year though

Answer 30

good for you, keep your eye on the prize wink wink lol

Answer 31

Thanks! :)