How Khan Academy Is Changing the Rules of Education
Matthew Carpenter, age 10, has completed 642 inverse trigonometry problems at KhanAcademy.org.
Photo: Joe Pugliese
“This,” says Matthew Carpenter, “is my favorite exercise.” I peer over his shoulder at his laptop screen to see the math problem the fifth grader is pondering. It’s an inverse trigonometric function: cos-1(1) = ?Read »