Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
sandy524
Group Title
find the derivative of f(x) = cos(x) − sin^2(x) on [0,2pi]
 one year ago
 one year ago
sandy524 Group Title
find the derivative of f(x) = cos(x) − sin^2(x) on [0,2pi]
 one year ago
 one year ago

This Question is Closed

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
i now know that its sin(x)(2cos(x)+1)
 one year ago

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
can yu guys help me find the critical points
 one year ago

myininaya Group TitleBest ResponseYou've already chosen the best response.0
Are you sure it ask you to find f'(x) on [a,b]?
 one year ago

myininaya Group TitleBest ResponseYou've already chosen the best response.0
If so, you did that. You are done.
 one year ago

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
yes. may you help me find the critical points of this now
 one year ago

myininaya Group TitleBest ResponseYou've already chosen the best response.0
Set f'(x)=0 and solve for x to find the critical numbers.
 one year ago

myininaya Group TitleBest ResponseYou've already chosen the best response.0
You only need to solve this on the interval [0,2 pi]
 one year ago

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
can we do it together please
 one year ago

myininaya Group TitleBest ResponseYou've already chosen the best response.0
You are already factored f'(x) Now set both factors equal to 0.
 one year ago

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
how? can we work out the problem
 one year ago

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
step by step please
 one year ago

myininaya Group TitleBest ResponseYou've already chosen the best response.0
Yes. I'm walking you through it. You have sin(x)*(1+2cos(x))=0 Set both factors equal to 0.
 one year ago

myininaya Group TitleBest ResponseYou've already chosen the best response.0
Just like if you have a*b=0 then either a=0 or b=0 or both=0
 one year ago

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
http://www.wolframalpha.com/input/?i=sin%28x%29%282cos%28x%29%2B1%29%3D0
 one year ago

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
this is all i have
 one year ago

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
im confused about the results
 one year ago

myininaya Group TitleBest ResponseYou've already chosen the best response.0
Use your unit circle. Keep in mind you only have to look between 0 and 2pi
 one year ago

myininaya Group TitleBest ResponseYou've already chosen the best response.0
You have sin(x)=0 or 1+2cos(x)=0 Solve both of these for the trig function. Solve the first one for sin(x) and solve the second one for cos(x). Tell me what you get after doing this.
 one year ago

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
sinx=pin
 one year ago

sandy524 Group TitleBest ResponseYou've already chosen the best response.0
\[\pi n\]
 one year ago

myininaya Group TitleBest ResponseYou've already chosen the best response.0
Well you are trying to solve sin(x)=0 for x. You could divide both sides by 1 since 1 will never be 0. Try solving this: sin(x)=0 Then we will come back to 1+2cos(x)=0
 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.