+0  
 
-3
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2
avatar+60 

I know how to graph them but it says I have to solve the system of equations...How do I solve that?

 May 7, 2019
 #1
avatar+106539 
+2

y  =  4 cos (x) + 1

y  = -cos (x) - 4              set the y's equal.....and we have

 

4cos (x) + 1  = -cos(x) - 4         add  cos (x), 4 to both sides

 

5cos (x) + 5  =  0        subtract  5 from both sides

 

5 cos (x)  = - 5              divide both sides by 5

 

cos (x)  =  -1

 

And this happens when x  =  pi    and x  = -pi

 

The intersection point(s) are

 

4cos (pi) + 1  =  -4 + 1  =  -3   ⇒     (pi, -3)         and

 

4cos(-pi) + 1  =  -4 + 1  =  - 3  ⇒  (-pi, -3)

 

See the graph here, GM : https://www.desmos.com/calculator/j9yashts7t

 

 

cool cool cool

 May 7, 2019
 #2
avatar+19792 
0

This is called 'solving by the graphical method'..... when you graph the two (or more ) equations......The points where they intersect is the solution set.

 May 7, 2019

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