Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
Solve each equation for 0 = x = 2π :
i) 2cos^(2)x + 3cosx – 2 = 0
ii) sinx = sqrt 3cosx
(Rewards for correct answer)
 one year ago
 one year ago
Solve each equation for 0 = x = 2π : i) 2cos^(2)x + 3cosx – 2 = 0 ii) sinx = sqrt 3cosx (Rewards for correct answer)
 one year ago
 one year ago

This Question is Closed

enkaBest ResponseYou've already chosen the best response.0
did you mean \[ (1)\quad2cos^2x+3cosx−2=0\\ (2)\quad \sin x=\sqrt{3}\cos x\\ \text{for }0\le x \le2\pi\] ???
 one year ago

darkb0nebeautyBest ResponseYou've already chosen the best response.0
a. (2cosx1)(cosx+2)=0 cosx=1/2 or cosx=2 x={π/3, 5π/6} This is correct, i promise...
 one year ago

ZeHanzBest ResponseYou've already chosen the best response.1
If you set p=cos x in the first one, you get: 2p²+3p2=0. You can solve this, using the quadratic formula. Once you've got you p, remember cos x = p, so solve for x.
 one year ago

darkb0nebeautyBest ResponseYou've already chosen the best response.0
Do you get mines @jahvoan
 one year ago

jahvoanBest ResponseYou've already chosen the best response.0
i got the answer but what is the corresponding angle for 2 on the unit circle?
 one year ago

ZeHanzBest ResponseYou've already chosen the best response.1
There isn't. cosx=2 has no solutions, because the xcoordinate of a point on the unit circle (which is the cosine) only has values from 1 to 1...
 one year ago

ZeHanzBest ResponseYou've already chosen the best response.1
You can divide both sides by cos x and remember sinx/cosx = tan x
 one year ago

jahvoanBest ResponseYou've already chosen the best response.0
but on the right it is sqrt cosx
 one year ago

ZeHanzBest ResponseYou've already chosen the best response.1
No, it's sqrt(3) * cosx
 one year ago

jahvoanBest ResponseYou've already chosen the best response.0
no look at the problem up top
 one year ago

ZeHanzBest ResponseYou've already chosen the best response.1
It says: sinx = sqrt 3cosx This can only mean:\[ \sin x = \sqrt{3} \cdot \cos x\]So dividing by cos x gives:\[\frac{ \sin x }{\cos x }=\sqrt{3} \Leftrightarrow \tan x=\sqrt{3}\]And this is a "nice" value of tan x. If you interpret it otherwise, you can't solve it...
 one year ago

jahvoanBest ResponseYou've already chosen the best response.0
so what will be the answer for sqrt 3 on the unit circle?
 one year ago

ZeHanzBest ResponseYou've already chosen the best response.1
Remember that special triangle with sides of a, 2a and a√3?
 one year ago

jahvoanBest ResponseYou've already chosen the best response.0
no its pi/3 right or wrong?
 one year ago

jahvoanBest ResponseYou've already chosen the best response.0
why is equation 2 not considered to be an identity?
 one year ago

ZeHanzBest ResponseYou've already chosen the best response.1
Identities hold for every x. This one is only true if x = pi/3. Identity: sinx=cos(pi/2x). No matter what x is, it's always true!
 one year ago
See more questions >>>
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
 Engagement 19 Mad Hatter
 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.