David Sinclair

"For decades, experts have believed that we are at the mercy of our genes, and that natural damage to our genes--the kind that inevitably happens as we get older--makes us become sick and grow old. But what if everything you think you know about aging is wrong? What if aging is a disease--and that disease is treatable? In Lifespan, one of the world's foremost experts on aging and genetics reveals a groundbreaking new theory that will forever change...

Why does it matter whether we state definitions carefully when we all know what particular geometric figures look like? What does it mean to say that a reflection is a transformation -- a function? How does the study of transformations and matrices in high school connect with later work with vector spaces in linear algebra? How much do you know, and how much do you need to know? Helping your students develop a robust understanding of geometry requires...