A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

Verify the identity. cotx minus pi divided by two. = -tan x

  • This Question is Closed
  1. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    \[\cot (x-\frac{ \pi }{ 2 })=-\tan x\]

  2. inkyvoyd
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    the answer is eggplants=eggplants

  3. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    oh come on help me out here :( i don't know how to use the confunction identities for cot.

  4. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    cofunction*

  5. inkyvoyd
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    tan=sin/cos cot=cos/sin sin(x-pi/2)=cos(x) etc

  6. inkyvoyd
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I mean my advice to you is to rewrite cot as cos/sin

  7. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    cos/sin=cot so cos=sin or cos = tan or cos = sec but thats only if cos(pi/2-u) but thats not the case in my problem

  8. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    my problem is (x-pi/2) not (pi/2-x)

  9. inkyvoyd
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    do you know even odd functions? sin(-x)=-sin(x) and cos(-x)=cos(x)

  10. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yes

  11. inkyvoyd
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    hence sin(x-pi/2)=sin(-(pi/2-x))=-sin(pi/2-x) and apologies for the typo earlier

  12. Mertsj
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    \[\cot (x-\frac{\pi}{2})=\frac{\cos (x-\frac{\pi}{2})}{\sin (x-\frac{\pi}{2})}=\frac{\cos x \cos \frac{\pi}{2}+\sin x \sin \frac{\pi}{2}}{\sin x \cos \frac{\pi}{2}-\cos x \sin \frac{\pi}{2}}\]

  13. inkyvoyd
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    o no mertsj typed something latexy that's better than what I have rip

  14. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    lol its no problem and true :p

  15. inkyvoyd
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    really though you need to negate your stuff on the inside and apply even odd functions to tak eout the negative sign and rewrite cot(x-pi/2) to cot(pi/2-x) (expand cot to cos/sin to do this)

  16. Mertsj
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    \[\frac{\cos x(0)+\sin x(1)}{\sin x(0)-\cos x(1)}=\frac{\sin x}{-\cos x}=-\tan x\]

  17. Mertsj
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 2

    And now you have proven the given identity once and for all.

  18. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ooooh i see i thought you had to make both of them negative thus making it tan=-tan i get it now ty!!!

  19. UsukiDoll
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    that was an intense one.. It probably needed one of the sum or difference identity formulas. right after rewriting cotx = cosx/sinx

  20. UsukiDoll
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    then evaluate it at pi/2 or 90 degrees ... terms cancel and viola -tanx =- tanx

  21. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.