Expression 3: StartFraction, sin left parenthesis, "x" StartRoot, "t" , EndRoot , right parenthesis Over StartRoot, "t" , EndRoot , EndFractionsinxtt
3
Expression 4: StartFraction, sinh left parenthesis, "x" StartRoot, negative "t" , EndRoot , right parenthesis Over StartRoot, negative "t" , EndRoot , EndFractionsinhx−t−t