# Question:A problem with using "subs" command

## Question:A problem with using "subs" command

Maple

While substituting expressions for θ(t),θ'(t),θ''(t) with some rather simple polynoms (see attached demonstration), the result icludes terms such as "·2" or "θ1·" (see terms multiplying ε8 and ε7in result for C1). It seems MAPLE treates the "·" sign as a variable/constant instead of as an operator. What am I doing wrong?

Screen capture:

Maple 1D Input:

thetaScaleDefinition := {diff(theta(t), `\$`(t, 1)) = (`#msub(mi("D"),mn("0",fontstyle = "italic"))`+epsilon*`#msub(mi("D"),mn("1",fontstyle = "italic"))`)*(epsilon*theta1+epsilon^2*`#mo("&sdot;",fontstyle = "italic")`*theta2), diff(theta(t), `\$`(t, 2)) = (`#msub(mi("D"),mn("0",fontstyle = "italic"))`^2+2*epsilon*`#msub(mi("D"),mn("0",fontstyle = "italic"))`*`#msub(mi("D"),mn("1",fontstyle = "italic"))`+epsilon^2*`#msub(mi("D"),mn("1",fontstyle = "italic"))`^2)*(epsilon*theta1+epsilon^2*theta2), theta(t) = epsilon*theta1+epsilon^2*theta2};

A1 := eta*mu*theta(t)*(diff(theta(t), t))^2/nu;

B1 := subs(thetaScaleDefinition, A1);

C1 := collect(B1, epsilon);

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