If y = cos(kt), then its first two derivatives are
y' = -k sin(kt)
y'' = -k² cos(kt)
Substituting y and y'' into 49y'' = -16y gives
-49k² cos(kt) = -15 cos(kt)
⇒ 49k² = 15
⇒ k² = 15/49
⇒ k = ±√15/7
Note that both values of k give the same solution y = cos(√15/7 t) since cosine is even.
Answer:
422.4cm²
Step-by-step explanation:
area of circle is pi x 12² which is 144 pi
144pi subtract 30 is 422.4
72/160=?
Divide 72 by 160 to find the percent.
72/160=0.45
72 is 45% of 160.
I hope this helps :)
Answer:
79
Step-by-step explanation:
4(13)+3(9)
52+27
79
