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x(t) = 12 cos (5t) + 4 sin (5t)                       

For which value of t the “Reduced Form” is equal to zero (x = 0) in the interval 0 < wt - phi < pi?

Pi = 3.14 
 

 Apr 27, 2016
 #1
avatar+33661 
+5

If x = 0 then 12 cos(5t) + 4sin(5t) = 0    

 

Rewrite as 4sin(5t) = -12cos(5t) 

 

Divide both sides by 4cos(5t) to get:    tan(5t) = -3

 

This gives 5t = tan-1(-3)  so  5t = 1.893 radians  (tan is negative in the 2nd quadrant)  

 

t = 1.893/5  = 0.379

.

 Apr 27, 2016
 #2
avatar+776 
0

THAT IS COMPLETLY RONG!!!!!!!!!!!!!!!!!!!!!!!!!!

THEY WERE TALKING ABOUT A FUNCTION!!!!!!!!!!!!!!!

User101  Apr 27, 2016
 #3
avatar+37146 
0

Same answer today, in Radians, that was derived by guest, in degrees yesterday.....this question just keeps going and going and going.....

 Apr 27, 2016

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