⌠ ⌡ cot x dx = | ⌠cos x ⌡sin x | dx |
set
u = sin x.
then we find
du = cos x dx
substitute du=cos x, u=sin x
| ⌠cos x ⌡sin x | dx = | ⌡u |
= ln |u| + C
substitute back u=sin x
= ln |sin x| + C⌠ ⌡ cot x dx = | ⌠cos x ⌡sin x | dx |
substitute du=cos x, u=sin x
| ⌠cos x ⌡sin x | dx = | ⌡u |
= ln |u| + C
substitute back u=sin x
= ln |sin x| + CCALCULATIONS INVOLVING LOGARITHMS
Because logarithms are exponents, mathematical operations involving them follow the same rules as those for exponents.
Common Logarithm | Natural Logarithm |
---|---|
log xy = log x + log y | Ln xy = Ln x + Ln y |
log x/y = log x - log y | Ln x/y = Ln x - Ln y |
log xy = y log x | Ln xy = y Ln x |
log y√x = log x1/y = (1/y )log x | Ln y√x = Ln x1/y =(1/y)Ln x |