Of course you can use the quotient rule, but it is usually not the easiest method. If we do use it here, we get $${d\over dx}{10\over x^2}={x^2\cdot 0-10\cdot 2x\over x^4}= {-20\over x^3},$$ since the derivative of 10 is 0.
1 Young children can't tell the difference between fantasy and reality. 2  Your preschooler's rich imagination is a big part of his normal development, but that means it is usually hard for him to tell the difference between what's real and what's imaginary.
What are nightmares? Nightmares are scary dreams that generally wake your child up from sleep and seem very real to him or her. Depending on your child's age, it is often difficult for children to separate a nightmare from reality, even after your child awakes from the nightmare.