Solving trig equations

Unicornstodope

New member
Joined
Aug 4, 2019
Messages
6
Can’t figure this equation out, can someone help?

sin^2 (5x)=1
 

Unicornstodope

New member
Joined
Aug 4, 2019
Messages
6
Please help me solve this equation.

2cos^2 (4theta) +3cos(4theta) +1=0
 

MarkFL

Super Moderator
Staff member
Joined
Nov 24, 2012
Messages
1,947

Unicornstodope

New member
Joined
Aug 4, 2019
Messages
6
Yes
 

MarkFL

Super Moderator
Staff member
Joined
Nov 24, 2012
Messages
1,947
For the first one, we get:

\(\displaystyle \sin(5x)=\pm1\)

This implies:

\(\displaystyle 5x=\frac{\pi}{2}+k\pi=\frac{\pi}{2}(2k+1)\) where \(k\in\mathbb{Z}\)

Hence:

\(\displaystyle x=\frac{\pi}{10}(2k+1)\)

Does this make sense? What do you get when factoring the second equation?
 

Unicornstodope

New member
Joined
Aug 4, 2019
Messages
6
I got this one
 

Unicornstodope

New member
Joined
Aug 4, 2019
Messages
6
Just need the first one please
 

MarkFL

Super Moderator
Staff member
Joined
Nov 24, 2012
Messages
1,947
I gave a complete solution for the first one, and I am hoping you will show you work on the second.
 

Unicornstodope

New member
Joined
Aug 4, 2019
Messages
6
The 1 first one is different I figured the second one
 

mmm4444bot

Super Moderator
Staff member
Joined
Oct 6, 2005
Messages
10,352
The [first] one is different[.] I figured the second one[.]
I tried to parse your wording, above. (Your last post is not clear, regarding what you're working on now or what kind of help you need.)

Please follow the forum guidelines (see the Read Before Posting notice). Show what you've started on the exercise you need help with, or explain why you're stuck.

In the future, please start a new thread for each new exercise. Cheers!

\(\;\)
 
Top