Trigonometry Help. pls

[chaoticaura]

Ugh, I feel kinda strange as this is my first post and im allready asking for help on this forum.. but im in need of help


Well ive got some vacation extra credit homework... but the problem is that I seem to have forgotten almost everything. A problem like this might be too hard to explain to me over a forum, since it has graphing and all.. but any help would be a preciated, to get me on the right track. I just need something to refresh my memory on this.

Graph y = sin(x), x = -360 ~ 360.
Find the y for x = 0, 30, 45, 60, 70, 80, and 90,
Create a table with above values for Quad. 1, 2,
3, and 4 before plotting. Do not sketch.

ive got several of these problems.. any help would be greatly apreciated.. oh and remember not to give me the answer (just in case my teacher is reading, not ment to be sarcastic or anything like that. im just here for some much needed help) allthough I doubt that would ever happen in a forum like this.

 

[Unco]

Graph y = sin(x), x = -360 ~ 360.
Find the y for x = 0, 30, 45, 60, 70, 80, and 90,

You can use your calculator here for the ones you can't remember. You might remember the exact value for sin(45deg).

Create a table with above values for Quad. 1, 2,
3, and 4 before plotting. Do not sketch.

                     90 deg
       2              |           1
                      |
                      |
      180 deg_________|__________ 0, 360 deg
                      |
                      |
       3              |
                     270 deg     4

Edit: Hey, doesn't that blue code look cool or what?!

 

[chaoticaura]

hmm

thx, for such a quick reply

hmm so for the first part..

Graph y = sin(x), x = -360 ~ 360.
Find the y for x = 0, 30, 45, 60, 70, 80, and 90,

I just substitute... the numbers in the equation y=sin(x), y=sin(0), y=sin(30), ect..

im still kinda confused about making a table though... ill try to look back on my notes from class and see if I can figure it out.. but any help would be a preciated.. thx alot for what you have allready helped me with. (im horrible at math sry if its frustrating >.<)


Edit: yeah, its a really preaty blue code.

 

[Unco]

I just substitute... the numbers in the equation y=sin(x), y=sin(0), y=sin(30), ect..

Yep!

im still kinda confused about making a table though... ill try to look back on my notes from class and see if I can figure it out

Take another look at my diagram of the quadrants. You can first draw in the angles 0, 30, 45, 60, 70, 80, and 90 (deg). See if you can fill in the other quadrants by symmetry to get corresponding angles from 90 to 360 deg. Remember that the angle is taken from the positive x-axis, if counter-clockwise the angle is positive, if clockwise it is negative.

Oh and I mentioned the colour because just today the forum got a new layout.

 

[chaoticaura]

ugh

thank you soooooooo much for your help... although im sorry I waisted your time... it seems to me like I forgot way too much of this stuff I dont understand a single thing anymore.. bleh and I dont even think im doing the calculator part right.. ive got 2 and I seem to be getting two different answers... for example sin(30)=0.5 and sin(30)=-0.98803162409287 I know I must be doing something horrobly wrong on my part.. and this probablem is probably just baby stuff to everyone... and even if I managed to get past that problem I still have to figure out the whole table thing.. (you explained it very well btw, its just that ive missed way too much of my trig class.. so I dont understand it one bit) I apologize for having used up your valuable time. =/

I hate giving up but I must throw in the towl... this assignment is due in this thursday.. I think ill have to give this another try tomorrow.. hopefully an uncle of mine can sit down with me and explain it to me step by step...

 

[Unco]

for example sin(30)=0.5 and sin(30)=-0.98803162409287

We are working in degrees so you must have your calculator in degrees. The -0.98... value is from your calculator being in radians.

 

[chaoticaura]

hits him self

*hits him self on the head*...... -.- should have checked what the calculator was set to =/ thx

im still confused with the whole make a table thing.... but I think ill just do everything I can do... and get some help from my uncle.. ive taken up way too much of your time allready.

 

[Euler]

Re: hits him self

*hits him self on the head*...... -.- should have checked what the calculator was set to =/ thx

im still confused with the whole make a table thing.... but I think ill just do everything I can do... and get some help from my uncle.. ive taken up way too much of your time allready.

Regarding the table, it seems like what the book is asking for is a table of values you get from plugging in (0, 30, 45, etc.) into the sin function.

So, it would look something like:

f(x)_____Degree
sin(0)_____0
sin(30) ___.5
sin(45)____.707107

etc. etc.

Now, quadrants 1 and 2 are going to give the same degrees for numbers that are equal distances away from the x axis. For example, sin(30) and sin(150) are going to give the same answer, because they are both 30 degrees away from the x-axis. Same goes for sin(45) and sin(135).