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.
Step-by-step explanation:
5 tank tops= $20
5 t-shirts= $35
20/5= 4
35/5=7
7-4=3
The t-shirts are $3 more than the tank tops
Answer:100 times 7
Step-by-step explanation: because
