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:
Order summands
2
Subtract
5
.
1
5.1
5.1
from both sides of the equation
3
Simplify
4
Divide both sides of the equation by the same term
5
Simplify
Step-by-step explanation:
Answer:
multiplication property of equality
Step-by-step explanation:
