This is not valid MATLAB syntax. There is no implied multiplication in MATLAB, so 2sin5t is not permitted syntax. Also, sin needs to be called as a function, such as sin(5*t)
It is also not valid to have an expression on the left hand side of an = statement.
The closest to those statements that you could get in MATLAB would be
syms t Xt x X
Xt == 2*sin(5*t)
ans =
x^2 == 5*sin(10*t)
ans =
X^3 == 10*sin(20*t)
ans =
This will not have much effect, as it is a series of equations and it is not assigning the equations to variables.