For what values of $k$ does the function $y = \cos k t$ satisfy the differential equation $49 y ^ { \prime \prime } = - 81 y$ ?
A)
$$k = - \frac { 1 } { 9 }$$
B) $k = \frac { 1 } { 9 }$
C)
$$k = - \frac { 9 } { 7 }$$
D) $k = \frac { 1 } { 7 }$
E) $k = \frac { 9 } { 7 }$

Question

Quizplus · Accepted Answer

The Answer of For what values of $k$ does the function $y = \cos k t$ satisfy the differential equation $49 y ^ { \prime \prime } = - 81 y$ ?
A)
$$k = - \frac { 1 } { 9 }$$
B) $k = \frac { 1 } { 9 }$
C)
$$k = - \frac { 9 } { 7 }$$
D) $k = \frac { 1 } { 7 }$
E) $k = \frac { 9 } { 7 }$

For What Values Of kkk Does the Function y=cos⁡kty = \cos k ty=coskt

For What Values Of $k$ Does the Function $y = \cos k t$