Jump to content

SO INREDIBLY URGENT


japmans
 Share

Recommended Posts

ok, i'm a scammer.. i know the title got you guys blush.gif

i had a quick question for the math geeks out there... my ability in trigonometry sucks royally... i have to solve this trig identity:

cos^2 2x + 2 cos 2x +1 = 0 , where the domain is from -pi to pi, or [-pi, pi]

if anyone can help me out, that'd be awesome.. like.. with the first couple steps, cuz i really have no idea what to do with that...

thanks anyone who can help..

Link to comment
Share on other sites

  • Replies 24
  • Created
  • Last Reply

Top Posters In This Topic

lol tahts a first.. anyway.. use the cos ^2 identity 1/2 (1 - cos 2x)

wat book r u using?

that's the wierd part.. it's not in a book.. she's teaching it to us seperately.. it's not even aprt of the curriculum, but she said that since ontario compressed one year of high school, the trig unit got left out of the calc course... so she's jus teachin us a bit so that its not AS difficult in univeristy, when we get exposed to it.

but yeah.. i cant figure it out..

1/2(1- cos 2x)

that means

cos^2 2x + 2 cos 2x + 1 = 0

1/2 (1 - cos 2x)...... but it was cos^2 2x.... so does the identity still apply to it?

Link to comment
Share on other sites

WJKK WJKF

hold on ... :@ .. i didnt do math in a while but cant you apply rule i forget its name... so u get two brackets...

(cos2x+1) (cos2x+1) = 0 ... if u expand that u will get the orginal. If u still dont know what i mean to solve it since brackets r da same just take one.. set it equal to 0 u should get ur x.

bhul chuk maph!

Link to comment
Share on other sites

Guest rsingh

Waheguroo Jee Ka Khalsa!

Waheguroo Jee Kee Fateh!!

drum roll please try this :@

Method:

cos ^2x + 2cos 2x +1 =0

factorsing the expression

(cos2x+1)(cos2X+1)

therefore

cos 2x=-1

2x = arccos (-1)

2x=pi

x=pi/2, 3pi/2, not sure about third part however the first three steps r corect.

answer= pi/2 or 3pi/2

hope it works Good LUCK

Waheguroo Jee Ka Khalsa!

Waheguroo Jee Kee Fateh!!

Link to comment
Share on other sites

oh wow.... thanks guys.. i actually didn't even think of that equation in the same resepct as a quadratic... that woulda helped me.. haha too bad i read this today and not last night... i already handed it in and i didn't even attampt that question..

thanks for your help though.. haha now i know where to turn for my next unit's trig section :@

Link to comment
Share on other sites

this is the way i did it:

cos^2 2x + 2cos 2x +1 =0

let us set (cos2x) = u

so we get;

u^2 + u + 1 = 0 and here the abc-formule can be used,

by doing so you get u = -1

ie.

cos 2x = -1

and then you take it across;

2x = pi

x = pi/2 + pi * k [the ans is pi/2 when you set k = 0, pi is the periode in this equa.]

3pi/2 would not be an ans here cause it is outside the domain [-pi,pi]

and the second ans in this domain will be:

x = pi/2 + pi * k [when k is -1]

->

x = -pi/2

so the answars for this equa between [-pi,pi] are: pi/2 and -pi/2

:@

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share


  • advertisement_alt
  • advertisement_alt
  • advertisement_alt


  • Topics

  • Posts

    • Net pay after taxes. If you don't agree, think about this: If you were a trader and started off in China with silk that cost 100 rupees and came to India, and you had to pay total 800 rupees taxes at every small kingdom along the way, and then sold your goods for 1000 rupees, you'd have 100 rupees left, right? If your daswandh is on the gross, that's 100 rupees, meaning you have nothing left. Obviously, you owe only 10% of 100, not 10% of 1000. No, it's 10% before bills and other expenses. These expenses are not your expenses to earn money. They are consumption. If you are a business owner, you take out all expenses, including rent, shop electricity, cost of goods sold, advertising, and government taxes. Whatever is left is your profit and you owe 10% of that.  If you are an employee, you are also entitled to deduct the cost of earning money. That would be government taxes. Everything else is consumption.    
    • No, bro, it's simply not true that no one talks about Simran. Where did you hear that? Swingdon? The entire Sikh world talks about doing Simran, whether it's Maskeen ji, Giani Pinderpal Singh, Giani Kulwant Singh Jawaddi, or Sants. So what are you talking about? Agreed. Agreed. Well, if every bani were exactly the same, then why would Guru ji even write anything after writing Japji Sahib? We should all enjoy all the banis. No, Gurbani tells you to do Simran, but it's not just "the manual". Gurbani itself also has cleansing powers. I'm not saying not to do Simran. Do it. But Gurbani is not merely "the manual". Reading and singing Gurbani is spiritually helpful: ਪ੍ਰਭ ਬਾਣੀ ਸਬਦੁ ਸੁਭਾਖਿਆ ॥  ਗਾਵਹੁ ਸੁਣਹੁ ਪੜਹੁ ਨਿਤ ਭਾਈ ਗੁਰ ਪੂਰੈ ਤੂ ਰਾਖਿਆ ॥ ਰਹਾਉ ॥ The Lord's Bani and the words are the best utterances. Ever sing hear and recite them, O brother and the Perfect Guru shall save thee. Pause. p611 Here Guru ji shows the importance of both Bani and Naam: ਆਇਓ ਸੁਨਨ ਪੜਨ ਕਉ ਬਾਣੀ ॥ ਨਾਮੁ ਵਿਸਾਰਿ ਲਗਹਿ ਅਨ ਲਾਲਚਿ ਬਿਰਥਾ ਜਨਮੁ ਪਰਾਣੀ ॥੧॥ ਰਹਾਉ ॥ The mortal has come to hear and utter Bani. Forgetting the Name thou attached thyself to other desires. Vain is thy life, O mortal. Pause. p1219 Are there any house manuals that say to read and sing the house manual?
    • All of these are suppositions, bro. Linguists know that, generally, all the social classes of a physical area speak the same language, though some classes may use more advanced vocabulary. I'm talking about the syntax. That is, unless the King is an invader, which Porus was not. When you say Punjabi wasn't very evolved, what do you mean? The syntax must have been roughly the same. As for vocabulary, do you really think Punjabis at the time did nothing more than grunt to express their thoughts? That they had no shades of meaning? Such as hot/cold, red/yellow/blue, angry/sweet/loving/sad, etc? Why must we always have an inferiority complex?
    • I still think about that incident now and then, just haven't heard any developments regarding what happened, just like so many other things that have happened in Panjab!
    • There was a young Singh from abroad who went to Anandpur Sahib Hola and got into a fight with some Punjabis who were playing loud non-religious music. He had bana and a weapon or two. There were more of them than him.  He ended up losing his life. Don't be like that. Not worth it to fight manmukhs. @californiasardar1 ਮੂਰਖੈ ਨਾਲਿ ਨ ਲੁਝੀਐ ॥੧੯॥ Argue not with a fool. p473
×
×
  • Create New...

Important Information

Terms of Use