🧒 0 · Explained for a 10-year-old (with animation)
Before any formulas, here's what differentiation and integration really are — using two simple animated pictures.
0.1 Differentiation = "How fast is it changing right now?"
Think of riding a bike on a hilly road. Your speedometer doesn't show your total trip — it shows how fast you are going right at this moment. That's exactly what differentiation does.
You give it a curve (your height above the ground, your bank balance over time, the position of a ball), and at any point along that curve it tells you "how steeply is it changing right now?"
Going UP a hill
Slope is positive. The bigger the climb, the bigger the number.dy/dx > 0At the TOP of a hill
Slope is zero — for a tiny moment you're flat.dy/dx = 0 (this is how we find peaks and valleys!)Going DOWN a hill
Slope is negative.dy/dx < 0Flat road
Slope is zero everywhere — nothing is changing.dy/dx = 0Differentiation answers "how fast is something changing at this exact moment?" In physics that becomes velocity (how fast position changes) and acceleration (how fast velocity changes).
0.2 Integration = "How much altogether?"
Think of filling a swimming pool with a hose. The hose might run fast at first, slow down for a while, then speed up again. To know the total water in the pool after some time, you can't just look at the speed at one moment — you have to add up everything that has flowed.
Integration is the maths version of that adding-up. Take the curve (the flow rate, the height of a hill, anything), slice it into super-thin vertical strips, multiply each strip's height by its tiny width dx, and sum them all. The result is the total area under the curve — and it tells you how much water reached the pool, how far the car drove, or how much charge flowed through a wire.
Tall slices
Curve is high → each rectangle is tall → that section contributes a LOT to the total.Short slices
Curve is low → small contribution. The "small bit" still counts!Curve below zero
Slice points DOWN — counts as NEGATIVE area (water leaves the pool).Thinner slices
The thinner you make them, the more accurate your total. In the limit (dx → 0) the answer is EXACT.Integration answers "how much, in total, has happened?" In physics that becomes distance (total of velocity over time), charge (total of current over time), or work (total of force over distance).
0.3 The two are opposites — the magic link
If differentiation breaks something into "how fast" pieces, then integration glues them back together. Apply one and then the other, you get back what you started with — they are perfect opposites.
That is why every formula in this page comes in pairs. Every derivative on the left side has a matching integral on the right. Master the derivatives and the integrals become much easier — they are just derivatives read backwards.
∂ 1 · What is Differentiation?
Differentiation finds the instantaneous rate of change of a quantity — the slope of a curve at one point.
dy/dx = limΔx → 0 [y(x + Δx) − y(x)] / ΔxTake two points on the curve very close together. Compute rise/run. Shrink the gap to zero. That number is the slope at the chosen point — its derivative.
1.1 Notation — three ways to write the same thing
| Notation | Read as | Used by |
|---|---|---|
dy/dx | "derivative of y with respect to x" | Leibniz (standard NEET) |
f′(x) | "f-prime of x" | Lagrange (most textbooks) |
ẏ or ẋ | "derivative w.r.t. time" | Newton (physics) |
1.2 The slope question for common curves
| Curve | Slope at any x | Slope at x = 1 |
|---|---|---|
y = x | 1 | 1 |
y = x² | 2x | 2 |
y = x³ | 3x² | 3 |
y = sin x | cos x | cos 1 ≈ 0.54 |
y = eˣ | eˣ | e ≈ 2.72 |
∂ 2 · The Five Rules of Differentiation
| Rule | Formula | Plain meaning |
|---|---|---|
| Constant | d/dx (c) = 0 | Constants don't change → slope is 0. |
| Constant multiple | d/dx (c · f) = c · f′ | Constants slide outside the derivative. |
| Sum / Difference | d/dx (u ± v) = u′ ± v′ | Differentiate each piece, add/subtract. |
| Power | d/dx (xⁿ) = n · xⁿ⁻¹ | Drop the power down, subtract 1. |
| Product | d/dx (u·v) = u′·v + u·v′ | "First × derivative of second + second × derivative of first." |
| Quotient | d/dx (u/v) = (u′·v − u·v′) / v² | Mind the minus sign and the v² in the denominator. |
| Chain | d/dx (f(g(x))) = f′(g(x)) · g′(x) | Differentiate outer, then multiply by derivative of inner. |
For xⁿ: "drop the power to the front, then drop the power by one." So x³ → 3x² · x → 1 · x⁵ → 5x⁴.
2.1 Tiny worked steps
5·3·x² + 2 − 0 = 15x² + 2
u = x²+1, u′ = 2x. v = x−3, v′ = 1.
Result = 2x(x−3) + (x²+1)(1) = 2x²−6x + x²+1 = 3x² − 6x + 1
Outer = sin(·), derivative = cos(·). Inner = 3x², derivative = 6x.
Result = cos(3x²) · 6x = 6x cos(3x²)
∂ 3 · Standard Derivatives — the must-know table
| f(x) | f′(x) | f(x) | f′(x) |
|---|---|---|---|
c (constant) | 0 | xⁿ | n·xⁿ⁻¹ |
x | 1 | 1/x | −1/x² |
√x | 1/(2√x) | ∛x | 1/(3 x²⁄³) |
eˣ | eˣ | aˣ | aˣ · ln a |
ln x | 1/x | loga x | 1/(x · ln a) |
|x| | x/|x| (sign) | eᵏˣ | k · eᵏˣ |
∂ 4 · Trigonometric & Inverse Trig Derivatives
4.1 Trigonometric functions
| f(x) | f′(x) | f(x) | f′(x) |
|---|---|---|---|
sin x | cos x | cos x | −sin x |
tan x | sec²x | cot x | −cosec²x |
sec x | sec x · tan x | cosec x | −cosec x · cot x |
4.2 Inverse trig functions
| f(x) | f′(x) | Domain |
|---|---|---|
sin⁻¹ x | 1/√(1 − x²) | −1 < x < 1 |
cos⁻¹ x | −1/√(1 − x²) | −1 < x < 1 |
tan⁻¹ x | 1/(1 + x²) | all x |
cot⁻¹ x | −1/(1 + x²) | all x |
sec⁻¹ x | 1/(|x|·√(x² − 1)) | |x| > 1 |
cosec⁻¹ x | −1/(|x|·√(x² − 1)) | |x| > 1 |
Every inverse-trig pair (sin⁻¹ / cos⁻¹, tan⁻¹ / cot⁻¹, sec⁻¹ / cosec⁻¹) has the same derivative magnitude with opposite signs.
∂ 5 · Exponential, Logarithmic & Hyperbolic
| f(x) | f′(x) |
|---|---|
eˣ | eˣ (its own derivative) |
ekx | k · ekx |
ef(x) | ef(x) · f′(x) |
aˣ | aˣ · ln a |
ln x | 1/x |
ln(f(x)) | f′(x)/f(x) |
loga x | 1/(x · ln a) |
sinh x | cosh x |
cosh x | sinh x |
tanh x | sech²x |
∂ 6 · Implicit & Logarithmic Differentiation
6.1 Implicit differentiation
Used when y is defined implicitly by an equation in x and y, not as y = f(x). Differentiate every term w.r.t. x, treating y as a function of x; collect dy/dx.
x² + y² = 25. Differentiate: 2x + 2y·(dy/dx) = 0 → dy/dx = −x/y.
6.2 Logarithmic differentiation — for y = (something)something
When the function has the variable in BOTH base and exponent (e.g. x^x, (sin x)cos x), use:
- Take ln of both sides.
- Use log laws to split into a sum.
- Differentiate both sides w.r.t. x.
- Multiply through by y.
ln y = x · ln x.
(1/y) dy/dx = ln x + x · (1/x) = ln x + 1.
So dy/dx = xˣ (ln x + 1).
6.3 Parametric differentiation
If x = x(t) and y = y(t):
dy/dx = (dy/dt) / (dx/dt)dx/dθ = −a sin θ. dy/dθ = a cos θ. dy/dx = (a cos θ)/(−a sin θ) = −cot θ
∂ 7 · Higher-Order Derivatives
| Order | Symbol | Physics meaning |
|---|---|---|
| 1st | dy/dx, f′(x) | Velocity (when y is position, x is t) |
| 2nd | d²y/dx², f″(x) | Acceleration |
| 3rd | d³y/dx³, f‴(x) | Jerk (rarely tested) |
| nth | dⁿy/dxⁿ, f(n)(x) | General |
If x(t) = A sin(ωt), then v = dx/dt = Aω cos(ωt), a = d²x/dt² = −Aω² sin(ωt) = −ω²x.
The minus sign in a = −ω²x is the signature of SHM.
∂ 8 · Where Differentiation Appears in NEET
8.1 Physics — Kinematics
v = dx/dt a = dv/dt = d²x/dt²8.2 Physics — Electromagnetism
EMF: ε = − dΦ/dt (Faraday's law)I = dQ/dt VL = L · dI/dt8.3 Physics — Maxima & Minima
To find a maximum or minimum of f(x):
- Solve
f′(x) = 0for stationary points. - If
f″(x) < 0at that point → maximum (curve bends down). - If
f″(x) > 0at that point → minimum (curve bends up).
Projectile range R = (u²/g)·sin(2θ). Set dR/dθ = 0: cos(2θ) = 0 → θ = 45°. That's why 45° gives the maximum range.
8.4 Chemistry — Kinetics
Rate = − d[reactant]/dt = + d[product]/dt8.5 Chemistry — Thermodynamics partials
(∂G/∂T)p = − S (∂G/∂p)T = V∫ 9 · What is Integration?
Integration is the reverse of differentiation — it finds the function whose derivative is the given one. Geometrically, the definite integral of f(x) from a to b equals the area under the curve y = f(x) between x = a and x = b.
If F′(x) = f(x), then ∫ f(x) dx = F(x) + CIf differentiation says "find the slope," integration says "given the slope at every point, find back the curve." The +C is the constant of integration — different curves can have the same slope (parallel curves shifted up or down).
9.1 Two basic properties
| Property | Formula |
|---|---|
| Constant multiple | ∫ c·f(x) dx = c · ∫ f(x) dx |
| Sum / Difference | ∫ [f(x) ± g(x)] dx = ∫ f(x) dx ± ∫ g(x) dx |
∫ 10 · Standard Integral Table
10.1 Power, exponential, log
| f(x) | ∫ f(x) dx |
|---|---|
xⁿ (n ≠ −1) | xⁿ⁺¹ / (n + 1) + C |
1/x | ln|x| + C |
eˣ | eˣ + C |
ekx | ekx/k + C |
aˣ | aˣ / ln a + C |
1/(x + a) | ln|x + a| + C |
10.2 Trigonometric integrals
| f(x) | ∫ f(x) dx |
|---|---|
sin x | −cos x + C |
cos x | sin x + C |
tan x | − ln|cos x| + C or ln|sec x| + C |
cot x | ln|sin x| + C |
sec x | ln|sec x + tan x| + C |
cosec x | ln|cosec x − cot x| + C |
sec²x | tan x + C |
cosec²x | −cot x + C |
sec x · tan x | sec x + C |
cosec x · cot x | −cosec x + C |
10.3 Inverse trig integrals
| f(x) | ∫ f(x) dx |
|---|---|
1/√(1 − x²) | sin⁻¹ x + C |
−1/√(1 − x²) | cos⁻¹ x + C |
1/(1 + x²) | tan⁻¹ x + C |
1/(|x|·√(x² − 1)) | sec⁻¹ x + C |
∫ 11 · Integration by Substitution
If the integrand contains a function and its derivative (or a near-multiple), substitute u = inner function.
∫ f(g(x)) · g′(x) dx = ∫ f(u) du (where u = g(x))11.1 Common patterns
| Integrand | Substitute | Result |
|---|---|---|
∫ (f(x))ⁿ · f′(x) dx | u = f(x) | (f(x))ⁿ⁺¹ / (n+1) + C |
∫ f′(x)/f(x) dx | u = f(x) | ln|f(x)| + C |
∫ f′(x) · ef(x) dx | u = f(x) | ef(x) + C |
∫ sin(ax + b) dx | u = ax + b | −cos(ax+b)/a + C |
∫ (ax + b)ⁿ dx | u = ax + b | (ax+b)ⁿ⁺¹ / [a(n+1)] + C |
∫ 2x / (x² + 1) dx. Let u = x² + 1, du = 2x dx. Integral = ∫ du/u = ln|u| + C = ln(x²+1) + C.
∫ 12 · Integration by Parts
Used when the integrand is a product of two functions that don't share a clean substitution.
∫ u dv = u·v − ∫ v du12.1 The "ILATE / LIATE" rule for picking u
Pick u from the function class that comes first in this priority list:
- I — Inverse trig (sin⁻¹ x, tan⁻¹ x …)
- L — Logarithmic (ln x, log x)
- A — Algebraic (xⁿ, polynomials)
- T — Trigonometric (sin x, cos x)
- E — Exponential (eˣ, aˣ)
u = x (algebraic), dv = eˣ dx. du = dx, v = eˣ.
∫ x eˣ dx = x · eˣ − ∫ eˣ dx = x eˣ − eˣ + C = eˣ (x − 1) + C
u = ln x, dv = dx. du = dx/x, v = x.
∫ ln x dx = x ln x − ∫ x · (1/x) dx = x ln x − x + C
12.2 Standard "by parts" result
∫ eˣ [f(x) + f′(x)] dx = eˣ · f(x) + C∫ 13 · Special / Standard Integrals
These should be memorised cold — they appear repeatedly in NEET physics problems.
13.1 Quadratic-denominator integrals
| Integrand | Answer |
|---|---|
1/(a² + x²) | (1/a) · tan⁻¹(x/a) + C |
1/(a² − x²) | (1/2a) · ln|(a + x)/(a − x)| + C |
1/(x² − a²) | (1/2a) · ln|(x − a)/(x + a)| + C |
1/√(a² − x²) | sin⁻¹(x/a) + C |
1/√(a² + x²) | ln|x + √(a² + x²)| + C |
1/√(x² − a²) | ln|x + √(x² − a²)| + C |
13.2 Square-root integrals
| Integrand | Answer |
|---|---|
√(a² − x²) | (x/2)√(a²−x²) + (a²/2) sin⁻¹(x/a) + C |
√(a² + x²) | (x/2)√(a²+x²) + (a²/2) ln|x + √(a²+x²)| + C |
√(x² − a²) | (x/2)√(x²−a²) − (a²/2) ln|x + √(x²−a²)| + C |
13.3 Reduction-style
| Integrand | Answer |
|---|---|
eᵃˣ · sin(bx) | eax(a sin bx − b cos bx)/(a² + b²) + C |
eᵃˣ · cos(bx) | eax(a cos bx + b sin bx)/(a² + b²) + C |
∫ 14 · Integration by Partial Fractions
For rational functions P(x)/Q(x) where deg(P) < deg(Q), split Q into simpler factors and write the rational as a sum.
| Form of Q(x) | Partial fraction |
|---|---|
| (x − a)(x − b) | A/(x−a) + B/(x−b) |
| (x − a)² | A/(x−a) + B/(x−a)² |
| (x − a)(x² + bx + c) | A/(x−a) + (Bx + C)/(x² + bx + c) |
| (x² + bx + c)² | (A x + B)/(x² + bx + c) + (Cx + D)/(x² + bx + c)² |
∫ dx/(x² − 1) = ∫ dx / [(x−1)(x+1)] = ½ ∫ [1/(x−1) − 1/(x+1)] dx = ½ ln|(x−1)/(x+1)| + C
∫ 15 · Definite Integrals & Their Properties
∫ab f(x) dx = F(b) − F(a) (where F′ = f)This is the Fundamental Theorem of Calculus — it links differentiation and integration.
15.1 Properties of definite integrals
| Property | Formula |
|---|---|
| Reverse limits | ∫ab f(x) dx = − ∫ba f(x) dx |
| Same limits | ∫aa f(x) dx = 0 |
| Split point | ∫ab f(x) dx = ∫ac f dx + ∫cb f dx |
| King property | ∫ab f(x) dx = ∫ab f(a + b − x) dx |
| Even integrand on (−a, a) | = 2 · ∫0a f(x) dx if f(−x) = f(x) |
| Odd integrand on (−a, a) | = 0 if f(−x) = −f(x) |
| Periodic (period T) | ∫0nT f(x) dx = n · ∫0T f(x) dx |
15.2 Area under a curve
Area under y = f(x) between x = a and x = b is ∫ab f(x) dx (if f ≥ 0)Area between two curves: ∫ab [fupper(x) − flower(x)] dx∫ 16 · Where Integration Appears in NEET
16.1 Physics — Kinematics
v(t) = v₀ + ∫₀t a(t) dt x(t) = x₀ + ∫₀t v(t) dtIf you know acceleration as a function of time, you INTEGRATE to find velocity. Integrate velocity to find position. Differentiation goes the other way (position → velocity → acceleration).
16.2 Physics — Work, Energy & Power
W = ∫ F · dx (work done by a variable force)U(x) = −∫ F(x) dx + C (potential energy)16.3 Physics — Electromagnetism
Q = ∫ I dt (charge flowing in time interval)V = ∫ E · dl (potential difference)Φ = ∫ B · dA (magnetic flux)16.4 Chemistry — Integrated rate laws
| Order | Differential form | Integrated form |
|---|---|---|
| Zero | −d[A]/dt = k | [A] = [A]₀ − kt |
| First | −d[A]/dt = k[A] | ln[A] = ln[A]₀ − kt |
| Second | −d[A]/dt = k[A]² | 1/[A] = 1/[A]₀ + kt |
16.5 Chemistry — Thermodynamic work
Wreversible isothermal = − nRT · ln(V2/V1) = − ∫V₁V₂ p dV🔑 17 · One-Page Cheat Sheet
Differentiation
| f(x) | f′(x) |
|---|---|
c | 0 |
xⁿ | n xⁿ⁻¹ |
eˣ | eˣ |
aˣ | aˣ ln a |
ln x | 1/x |
sin x / cos x | cos x / −sin x |
tan x / cot x | sec²x / −cosec²x |
sec x / cosec x | sec x tan x / −cosec x cot x |
sin⁻¹ x / cos⁻¹ x | ±1/√(1−x²) |
tan⁻¹ x | 1/(1+x²) |
| Product | u′v + uv′ |
| Quotient | (u′v − uv′)/v² |
| Chain | f′(g(x))·g′(x) |
| Max / min | f′ = 0; check sign of f″ |
Integration
| f(x) | ∫ f(x) dx |
|---|---|
xⁿ (n ≠ −1) | xⁿ⁺¹/(n+1) + C |
1/x | ln|x| + C |
eˣ | eˣ + C |
aˣ | aˣ/ln a + C |
sin x | −cos x + C |
cos x | sin x + C |
sec²x | tan x + C |
1/(1+x²) | tan⁻¹ x + C |
1/√(1−x²) | sin⁻¹ x + C |
1/(a²+x²) | (1/a) tan⁻¹(x/a) + C |
1/√(a²−x²) | sin⁻¹(x/a) + C |
| By parts | ∫ u dv = uv − ∫ v du (ILATE) |
| Substitution | u = inner function; replace dx |
| Definite | ∫ab f dx = F(b) − F(a) |
1) Power → drop, subtract. Inverse: Power → add, raise.
2) Three product/quotient/chain rules + ILATE solve 90 % of NEET integrals.
3) The constants
+C, ln a, and 1/(n+1) are the three things students forget most — flag them.