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 is the real difference? Think scuba diving vs. going to the aquarium. With virtual reality, you can swim with sharks. And with augmented reality, you can watch a shark pop out of your business card. While VR is more immersive, AR provides more freedom for the user, and more possibilities for marketers because it does not need to be a head-mounted display.