help me to find two consecutive differentiation with respect to x?

n/a

[Mischa Kim]

How about doing it by hand?

[Thorsten]

Have you looked at my answer?

[Rena Berman]

(Answers Dev) Restored Question.

Answer 1

[Thorsten]

If I remember my high-school algebra correctly, it's

q = 3*(1-cos(pi*x/10))= 3 - 3*cos(pi/10*x)
dq/dx = 3*sin(pi/10*x)*pi/10;
(d/dx)(dq/dx)= dq/dx^2 = 3*cos(pi/10*x)*pi^2/100;

[Thorsten]

Thank you for the correction. I corrected it above.