SOLUTION: lim cosx - cos3x /x^2 x-o lim 1-cos4x /xsin2x x-o

Algebra ->  Sequences-and-series -> SOLUTION: lim cosx - cos3x /x^2 x-o lim 1-cos4x /xsin2x x-o       Log On


   



Question 387635: lim cosx - cos3x /x^2
x-o
lim 1-cos4x /xsin2x
x-o

Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
I would advise you to insert parentheses so that the question becomes less ambiguous. For the first problem, I interpret it as:

lim%28x-%3E0%2C+%28cos+x+-+%28cos+%283x%29%29%2Fx%5E2%29%29 (by the order of operations)

= lim%28x-%3E0%2C+%28%28x%5E2+%28cos+x%29+-+cos%283x%29%29%2Fx%5E2%29%29

The numerator approaches -1 (by direct substitution) while the denominator approaches zero. Thus, the limit approaches negative infinity.

The second problem is similar, you may or may not have to use L'Hopital's rule to rewrite the limit.