This Double Integral Trips Up Students — Here's How to Solve It the Right Way

Learn how to evaluate the double integral I = ∫₁² ∫₂⁴ (x + 2y) dx dy using iterated integration — a foundational multivariable calculus skill for students bridging from Further Mathematics into university-level calculus. In this step-by-step tutorial, you'll learn: ✅ How to read and set up a double (iterated) integral ✅ Integrating (x + 2y) with respect to x first, treating y as a constant ✅ Evaluating the outer integral over the limits y = 1 to 2 ✅ Applying Fubini's Theorem to solve double integrals correctly ✅ Common mistakes students make when evaluating double integrals Whether you're a Further Mathematics student preparing for university or a first/second-year student tackling Calculus 3 (Multivariable Calculus), this video breaks the process down clearly and simply. 📌 Topics: double integrals, iterated integrals, multivariable calculus, definite integrals, Fubini's Theorem, integration techniques, calculus tutorial, Further Mathematics, university calculus for Nigerian students. 👉 Subscribe to Earl Samm Plus for more Further Mathematics and university calculus tutorials. #DoubleIntegral #MultivariableCalculus #FurtherMathematics #CalculusTutorial #IteratedIntegral #FubinisTheorem #MathTutorial #EarlSammPlus #UniversityCalculus