Final answer:
The differential of the function g(x,t)=x² is dg = 2x dx.
Step-by-step explanation:
To find the differential of the function g(x,t)=x², we differentiate the function with respect to x and t separately. Differentiating with respect to x, we get dg/dx = 2x. Differentiating with respect to t, we get dg/dt = 0 since x is not a function of t. Therefore, the differential of g(x,t) is given by dg = 2x dx.