your title is misleading ... x is defined in terms of a single variable, t
,
chain rule ...
clean up the algebra and use the quotient/chain rule to find
note that > 0 for
a particle moves along a horizontal line so that its coordinate at time t is x=(b^{2}+c^{2}t^{2})^(1/2), t is greater than or equal to 0, where b and c are positive constants
a.) find the velocity and acceleration functions
b.)show that the particle always moves in the positive direction