+45 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?
+37146 when t = 21.688 x = 0
Sure x= 0 = 12cos(5t) + 4sin(5t)
re-arranging 12cos(5t) = -4sin5t
-12/4 = sin5t / cos5t (remember sin/ cos = tan)
-3 = tan5t
Arctan(-3) = 5t
-71.565 or 108.43 (this is the only answer between 0 and pi) = 5t t = 21.686
+37146 when t = 21.688 x = 0
Sure x= 0 = 12cos(5t) + 4sin(5t)
re-arranging 12cos(5t) = -4sin5t
-12/4 = sin5t / cos5t (remember sin/ cos = tan)
-3 = tan5t
Arctan(-3) = 5t
-71.565 or 108.43 (this is the only answer between 0 and pi) = 5t t = 21.686
