# Trigonometric limit problem

#### dome34

Hi,
I have a problem which needs to be solved without using L'Hosiptal rule.
Can anyone help me?

#### skeeter

Math Team
try the substitution $u=\sqrt[6]{\cos{x}}$ ...

limit = $-\dfrac{1}{12}$

idontknow

#### idontknow

now the limit is $$\displaystyle \lim_{u\rightarrow 1 } \dfrac{u^3 - u^2 }{1-u^{12} }$$.

#### dome34

Is the following substitution correct? cosx = t^6