Some Useful Formulae
Exam Revision Formula Sheet
sin(ix) = i sinh(x)
cos(ix) = cosh(x)
sin x = (e^(ix) - e^(-ix)) / (2i)
cos x = (e^(ix) + e^(-ix)) / 2
sinh^2 x = (cosh(2x) - 1) / 2
cosh^2 x = (cosh(2x) + 1) / 2
Integral a^x dx = a^x / log a, where a > 0 and a != 1
Integral sinh(ax) dx = cosh(ax) / a
Integral cosh(ax) dx = sinh(ax) / a
Integral tanh(ax) dx = (1 / a) log(cosh(ax))
Integral dx / sqrt(a^2 - x^2) = sin^(-1)(x / a)
Integral dx / sqrt(x^2 - a^2) = log(x + sqrt(x^2 - a^2))
Integral dx / (x^2 + a^2) = (1 / a) tan^(-1)(x / a)
Integral sqrt(a^2 - x^2) dx = (x / 2) sqrt(a^2 - x^2) + (a^2 / 2) sin^(-1)(x / a)
Integral e^(ax) sin(bx) dx = e^(ax) (a sin(bx) - b cos(bx)) / (a^2 + b^2)
Integral e^(ax) cos(bx) dx = e^(ax) (a cos(bx) + b sin(bx)) / (a^2 + b^2)
Integral sec(ax) dx = (1 / a) log|sec(ax) + tan(ax)|
Integral cosec(ax) dx = (1 / a) log|cosec(ax) - cot(ax)|
sin x = x - x^3 / 3! + x^5 / 5! - ...
cos x = 1 - x^2 / 2! + x^4 / 4! - ...
tan x = x + x^3 / 3 + 2x^5 / 15 + 17x^7 / 315 + ...
log(1 + x) = x - x^2 / 2 + x^3 / 3 - x^4 / 4 + ...
log(1 - x) = -x - x^2 / 2 - x^3 / 3 - x^4 / 4 - ...
sinh x = x + x^3 / 3! + x^5 / 5! + ...
d/dx (a^x) = a^x log_e(a)
d/dx (cos^(-1) x) = -1 / sqrt(1 - x^2)
d/dx (cot^(-1) x) = -1 / (1 + x^2)
d/dx (cosec^(-1) x) = -1 / (|x| sqrt(x^2 - 1))
d/dx (log_a x) = 1 / (x log_e(a))
d/dx (tan^(-1)(x / a)) = a / (a^2 + x^2)