A community for students.
Here's the question you clicked on:
 0 viewing
ad2h
 10 months ago
Session 56, first recitation  a mistake? Why is the final answer 2√2 and not 4√2?
ad2h
 10 months ago
Session 56, first recitation  a mistake? Why is the final answer 2√2 and not 4√2?

This Question is Closed

phi
 10 months ago
Best ResponseYou've already chosen the best response.1I assume you get to \[  \cos(x)  \sin(x) \] evaluated from pi/4 to 5pi/4 we get the expression \[  \cos\left(\frac{5 \pi}{4}\right) \sin \left(\frac{5 \pi}{4}\right)  \left( \cos\left(\frac{ \pi}{4}\right) \sin \left(\frac{ \pi}{4}\right)\right) \\=  \cos\left(\frac{5 \pi}{4}\right) \sin \left(\frac{5 \pi}{4}\right) +\cos\left(\frac{ \pi}{4}\right)+ \sin \left(\frac{ \pi}{4}\right) \] use the values: \[ \cos\left(\frac{5 \pi}{4}\right)= \sin\left(\frac{5 \pi}{4}\right)=  \frac{\sqrt{2}}{2} \\ \cos\left(\frac{\pi}{4}\right)= \sin\left(\frac{\pi}{4}\right)= \frac{\sqrt{2}}{2} \] to get \[ \left(  \frac{\sqrt{2}}{2}\right) \left(  \frac{\sqrt{2}}{2}\right)+\frac{\sqrt{2}}{2}+\frac{\sqrt{2}}{2}\\= \frac{\sqrt{2}}{2}+\frac{\sqrt{2}}{2}+ \frac{\sqrt{2}}{2}+\frac{\sqrt{2}}{2} \\= \frac{4\sqrt{2}}{2} = 2 \sqrt{2}\]

ad2h
 10 months ago
Best ResponseYou've already chosen the best response.0Oh, sorry, I was confusing the trigonometric values to be square root of two instead of square root of two over two. Silly lack of attention.
Ask your own question
Sign UpFind 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.