Use l’Hôpital’s rule to find lim(csc(x) - cot(x)) as x -> 0.

This question relies partially on remembering the trigonometric identities, csc(x) = 1/(sin(x)) and cot(x) = 1/(tan(x)) = cos(x)/sin(x). Plugging these values into the equation, we want to find Lim((1-cos(x))/sin(x)) as x -> 0.

l'Hôpital's rule states that we can differentiate the top and bottom of the fraction separately and the limit will stay the same (note: we are not differentiating the fraction as a whole, this requires the quotient rule, but instead differentiating the numerator and denominator individually).

We do so to get that the limit is now Lim((sin(x)/cos(x)) as x -> 0 which is just 0. Therefore, the limit of the original equation is 0.

FS

Related Further Mathematics IB answers

All answers ▸

Prove that the function f:ZxZ -> ZxZ defined by f(x,y) = (2x+y,x+y) is a bijetion.


Prove that i^i is real.


How can we check that a numerical series is convergent?


Which test for convergence is the best for which series?