Question

cos 5 theta + cos 3 theta =0

Answer 1

Welcome to OpenStudy @bbj2512b! :)

Answer 2

\[\huge\color{blue}{ Cos(5θ) +Cos(3θ)=0 }\]

Way 1:
\[\color{blue}{ Cos(5θ) +Cos(3θ)=0 }\]\[\color{blue}{ Cos(5θ)=-Cos(3θ) }\]\[\color{blue}{ Cos(5θ) =Cos(3θ) }\]\[\color{blue}{ 5θ=3θ }\]\[So,~~~~θ~~~~is~~~~zero.\]

Also (#2) :
\[\color{blue}{ Cos(5θ)+Cos(3θ)=0 }\]\[\color{blue}{ Cos(4θ+θ)+Cos(4θ-0)=0 }\]
See?

Answer 3

The last equation in blue should be, \[Cos(4θ+θ)+Cos(4θ-θ)=0\]

Answer 4

http://www.ies-math.com/math/java/trig/kahote/kahote.html

Answer 5

I got disconnected.

Answer 6

solve the equation by first transforming it into a product equal to 0 and then setting each factor equal to 0. use the following domain [0,360] in degrees or [0,2 pi] in radian cos 5 theta + cos 3 theta =0

Answer 7

Oh, Idk how to do that, sorry :(

Answer 8

Try tagging someone else like this, @bbj2512b

Answer 9

thank you

Answer 10

\[
-\cos(3\theta) \neq \cos(3\theta)
\]And also, \(\theta = 0\) isn't even a solution since \(\cos(0) = 1\).