Master the concept of definite integrals in this comprehensive XO Math video lesson. We’ll build your understanding from the ground up—starting with Riemann sums, the formal definition of a definite integral, and the idea of signed area. You'll learn how to: Use graphical representations and geometry to evaluate definite integrals Understand the properties and notation of definite integrals Apply symmetry (even/odd functions) to simplify integrals Use the comparison theorem to bound definite integrals Solve step-by-step examples involving line segments, absolute value functions, semicircles, and more This lesson connects the ideas of limits, antiderivatives, and area under a curve to give you a full picture of how definite integrals work in calculus. For more video lessons and additional resources, visit www.xomath.com.