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Single Variable Calculus
Differentiation
01The Derivative as the Slope of the Tangent Line02Secant Lines and the Limit Definition of the Derivative03Differentiating 1/x Straight From the Definition04Tangents to 1/x and the Triangle of Area 205Newton and Leibniz Notation, and the Power RuleProblem set0/10Problem set 20/10MIT problem set0/3
01The Derivative as an Instantaneous Rate of Change02Rates of Change Without Time: Gradient and Sensitivity03Easy Limits, 0/0, and One-Sided Limits04Continuity, Jumps, and Removable Discontinuities05Infinite Discontinuities: 1/x and Its Derivative06Differentiable Implies ContinuousProblem set0/10Problem set 20/10
01Two Kinds of Formula, and the Derivative of Sine02The Derivative of Cosine, and Two Limits at Zero03Bow and Bowstring: Proving the Two Trig Limits04Why the Trig Derivatives Hold Only in Radians05A Geometric Proof: Sine as a Height on the Circle06Finishing the Proof, and the Product and Quotient RulesProblem set0/10Problem set 20/10MIT problem set0/1
01Proving the Product Rule: Change One Factor at a Time02The Quotient Rule, and the Power Rule for Negative Exponents03The Chain Rule: Differentiating a Function of a Function04Higher Derivatives: The Sine Cycle and Three Notations05The nth Derivative of xⁿ Is n Factorial, by InductionProblem set0/10Problem set 20/10MIT problem set0/2
01The Power Rule for Rational Exponents02The Slope of a Circle, Two Ways03Implicit Differentiation of a Quartic Curve04Inverse Functions and the Reflection Across y = x05Derivatives of the Arctangent and ArcsineProblem set0/10Problem set 20/10MIT problem set0/1
01The Derivative of aˣ and the Mystery Number M(a)02Defining e by Slope One, and the Derivative of ln x03M(a) = ln a: Differentiating aˣ and xˣ04Why (1 + 1/n)ⁿ Approaches eProblem set0/10Problem set 20/10MIT problem set0/1
Applications of Differentiation
01Linear Approximation: A Curve Is Its Tangent Line02Five Linear Approximations at Zero03Combining Approximations, from Algebra to GPS Clocks04Quadratic Approximation: The Best-Fit ParabolaProblem set0/10Problem set 20/10MIT problem set0/1
01Linear Approximation as a Proportionality Rule02Quadratic Approximation: Why the ½, and Products03Curve Sketching: The Sign of f′ and Critical Points04Curve Sketching: Ends, Concavity and InflectionProblem set0/10Problem set 20/10MIT problem set0/1
01Sketching Without Critical Points: (x+1)/(x+2)02A Five-Step Curve-Sketching Scheme, Applied to x / ln x03x / ln x: Inflection Point and Where Max and Min Can OccurProblem set0/10Problem set 20/10
01Two Squares From One Wire: The Critical Point Gives the Least Area02The Open Box of Fixed Volume: Least Material When x = 2y03Related Rates: The Police Radar and the Conical TankProblem set0/10Problem set 20/10MIT problem set0/4
01The Hanging Ring: Why the String Makes Equal Angles02Newton's Method: Tangent Lines That Find the Square Root of Five03Why Newton's Method Doubles Its Digits, and How It Fails04The Mean Value Theorem: Somewhere You Hit Your Average Speed05Positive Derivative Means Increasing: Proving eˣ Exceeds 1 + xProblem set0/10Problem set 20/10MIT problem set0/2
Integration
01Differentials: dy = f′(x) dx and the Cube Root of 64.102Antiderivatives Differ Only by a Constant03Integration by Substitution and Advanced GuessingProblem set0/10Problem set 20/10MIT problem set0/1
01Separation of Variables: dy/dx = −xy and the Bell Curve02General Solutions: Signs, Constants and Initial Conditions03Orthogonal Trajectories: Parabolas and Crossing EllipsesProblem set0/10Problem set 20/10MIT problem set0/1
01The Definite Integral: Area as a Limit of Rectangle Sums02Area Under y = x²: Squeezing the Sum of Squares03Sigma Notation and the Area Pattern: b, b²/2, b³/304Riemann Sums: the Definite Integral and a Year of LoansProblem set0/10Problem set 20/10MIT problem set0/1
01The Fundamental Theorem of Calculus: Area in One Line02Net Change and Signed Area: Integrating Velocity03Six Rules for Definite Integrals and Bounds on eᵇ04Substitution in Definite Integrals: Change the LimitsProblem set0/10Problem set 20/10MIT problem set0/1
01Average Rate Times Time: FTC Beats the Mean Value Theorem02Second Fundamental Theorem: Differentiate an Integral03Proving FTC1 and FTC2 with the Mean Value TheoremProblem set0/10Problem set 20/10MIT problem set0/2
Applications of Integration
01The Natural Log Defined as an Area Under 1/t02Functions With No Formula: erf, Fresnel and Li(x)03Setting Up the Area Between Two Curves04Vertical vs Horizontal Slices: One Region, Two IntegralsProblem set0/10Problem set 20/10

Vertical vs Horizontal Slices: One Region, Two Integrals

Why does slicing one region vertically need two integrals while slicing it horizontally needs only one?


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Your summary note

    1. 1

      Vertical slices and the split at x=1x = 1x=1

      Write the top y=xy = \sqrt{x}y=x​ and both bottom formulas, mark where the bottom changes at x=1x = 1x=1, and set up ∫012x dx+∫14(x−x+2) dx\int_0^1 2\sqrt{x}\,dx + \int_1^4 (\sqrt{x} - x + 2)\,dx∫01​2x​dx+∫14​(x​−x+2)dx.

    2. 2

      Horizontal slices as a single integral in yyy

      Rewrite the boundaries as left x=y2x = y^2x=y2 and right x=y+2x = y + 2x=y+2, take the limits y=−1y = -1y=−1 to y=2y = 2y=2, and set up ∫−12(y+2−y2) dy\int_{-1}^{2} (y + 2 - y^2)\,dy∫−12​(y+2−y2)dy.

    3. 3

      Checking right minus left, and the area 92\frac{9}{2}29​

      Show y+2−y2y + 2 - y^2y+2−y2 is positive on [−1,2][-1, 2][−1,2] and equals zero at both crossing points, then evaluate the antiderivative between the limits to reach the area 92\frac{9}{2}29​.

    Attempt 1 of 2