A community for students. Sign up today!
Here's the question you clicked on:
 0 viewing

This Question is Open

phi
 5 months ago
Best ResponseYou've already chosen the best response.0They are saying it is easy to find the derivative of cos(x) and evaluate it at x= pi/2 \[ \cos'(x)\bigg_{x= \frac{\pi}{2} }= ?\] The other idea is that the expression \[ \lim_{x\rightarrow \frac{\pi}{2} } \frac{\cos(x)}{x\frac{\pi}{2}}\] is vaguely reminiscent of the definition of the derivative \[ f'(x) = \lim_{\Delta\rightarrow 0} \frac{ f(x+\Delta) f(x)}{\Delta}\] Now if you can show that the given expression can be rewritten to look like the definition of the derivative, then you can claim that it and the derivative (evaluated at pi/2) have the same value (1 in this case) I would begin by letting \( x = \frac{\pi}{2} + \Delta \) in the given expression.
Ask your own question
Ask a QuestionFind more explanations on OpenStudy
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.