Calculus

Differentiation

From first principals

f'(x) = lim f(x+h)-f(x)
...............…..h

Stationary points

f'(x) = 0

Chain rule

dy/dx = dy/du x du/dx

Points of inflection

f''(x) = 0

e^x, ln x, a^x

d/dx e^f(x) = f'(x)e^f(x)

d/dx ln f(x) = f'(x)/f(x)

d/dx a^x = a^x ln a

Trig

d/dx sin ax = acos x

d/dx cos ax = -asin x

d/dx tan ax = asec^2 x

Product rule

y = f(x)g(x)
dy/dx = f'(x)g(x) + f(x)g'(x)

d/dx cosec x = -cosec x cot x

d/dx sec x = sec x tan x

d/dx cot x = -cosec^2 x

Quotient rule

y = f(x)/g(x)
dy/dx = f'(x)g(x) - f(x)g'(x)
.....................g(x)^2

Integration

e^x, 1/x

∫ e^f(x) dx = 1/f'(x)e^f(x) + C

∫ 1/f(x) dx = 1/f'(x) ln|f(x)| + C

f'(x)/f(x) dx = ln|f(x)| + C

Trig

∫ sin x dx = -cos x + C

∫ cos x dx = sin x +C

sec^2 x dx = tan x + C

Substitution

∫ f'(x)[f(x)]^n dx
u = f(x)
dx = du/f(x)

Parts

u dv/dx dx = uv - v du/dx dx

tan x dx = ln|sec x| + C

cot x dx = ln|sin x| + C