Question

Lena is playing her accordion by compressing and stretching it. The accordion's length (in cm) t seconds

Answer 1

Answer:

It takes Lena 4.1 seconds to compress the accordion completely and then stretch it back out to a length  of 50cm.

Step-by-step explanation:

I am assuming the function without a T: $A(t)= 25cos(t)+65$.

The function is graphed in the figure attached, and the blue line is $y =50cm$.

From the graph we see that the accordion is completely stretched  (has minimum length) at $t= \pi$ seconds, and stretches back  to 50cm at $t=4.069s$; therefore, it takes Lena 4.069 seconds to stretch the accordion back again, which to the nearest tenth of a second is  4.1s