Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
cos theta = 4/5, 0˚< theta < 90˚ use the information given to find sin2theta, cos2theta, and tan 2theta
 one year ago
 one year ago
cos theta = 4/5, 0˚< theta < 90˚ use the information given to find sin2theta, cos2theta, and tan 2theta
 one year ago
 one year ago

This Question is Closed

satellite73Best ResponseYou've already chosen the best response.1
you need \(\sin(\theta)\) so compute these do you know how to find it?
 one year ago

satellite73Best ResponseYou've already chosen the best response.1
dw:1358823887705:dw
 one year ago

alanli123Best ResponseYou've already chosen the best response.0
sin 2 theta = 2 sin theta cos theta cos 2 theta = 2 cos ^2 theta  1 tan 2 theta = sin 2 theta / cos 2 theta
 one year ago

abbyl94Best ResponseYou've already chosen the best response.0
do i plug in 4/5 where theta is?
 one year ago

AzteckBest ResponseYou've already chosen the best response.1
If costheta=4/5 then sintheta= 3/5 \[\sin2\theta=2\sin\theta \cos\theta\]
 one year ago

satellite73Best ResponseYou've already chosen the best response.1
there is a picture of an angle whose cosine is \(\frac{4}{5}\) you find the third side by pythagoras, or recalling the 3  4  5 right triangle this tells you \(\sin(\theta)=\frac{3}{5}\)
 one year ago

abbyl94Best ResponseYou've already chosen the best response.0
so 2 sin theta = 2 sin 3/5 cos 4/5
 one year ago

satellite73Best ResponseYou've already chosen the best response.1
no do not make that mistake, it is a common one do not use \(\theta=\frac{4}{5}\) use \(\cos(\theta)=\frac{4}{5}\) so \[\sin(2\theta)=2\times \frac{4}{5}\times \frac{3}{5}\]
 one year ago

satellite73Best ResponseYou've already chosen the best response.1
no not the cosine and sine of those numbers, those numbers ARE the cosine and sine
 one year ago

satellite73Best ResponseYou've already chosen the best response.1
use the numbers themselves, they are your sines and cosines
 one year ago

satellite73Best ResponseYou've already chosen the best response.1
your good now right?
 one year ago

abbyl94Best ResponseYou've already chosen the best response.0
im still confused a little ..
 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.