View Full Version : Horrible Calculus - Help!
toosm:)ey
Oct30-04, 04:24 PM
Hello everyone!
I have a calculus midterm next week and I need some help solving old midterm questions. I'm a first year calculus student so they're not hard, but I can't figure them out!
I am told to solve without using the tan addition formula.
toosm:)ey
Oct30-04, 04:27 PM
problem number 2
arildno
Oct30-04, 04:29 PM
Since:
tan(\frac{\pi}{6})=\frac{1}{\sqrt{3}}
the question merely asks you to calculate the derivative of tan(x) at x=\frac{\pi}{6}
arildno
Oct30-04, 04:30 PM
For your other questions, show some of your own work on these.
toosm:)ey
Oct30-04, 04:35 PM
Sure, but how do I use the code thing? Or is there an easy way to type out the work I have?
arildno
Oct30-04, 04:44 PM
Sure, but how do I use the code thing? Or is there an easy way to type out the work I have?
Click on a given "LATEX" code to see how you generate it. There's a sticky in General Physics which tells you a bit about it.
toosm:)ey
Oct30-04, 05:18 PM
\lim_{h\rightarrow0} \frac{1}{h}} (\frac{sin(h+(\pi/6))}{cos(h+(\pi/6))}} - \frac{1}{\sqrt3}})
\lim_{h\rightarrow0} \frac{1}{h}} (\frac{sin(x)cos(\pi/6) + cos(x)sin(\pi/6)}{cos(x)cos(\pi/6) + sin(x)sin(\pi/6)}} - \frac{1}{\sqrt3}})
\lim_{h\rightarrow0} \frac{1}{h}} (\frac{sin(x)(\sqrt3/2) + cos(x)(1/2)}{cos(x)(\sqrt3/2) + sin(x)(1/2)}} - \frac{1}{\sqrt3}})
\lim_{h\rightarrow0} \frac{1}{h}} ({\frac{\sqrt3sin(x) + cos(x)}{{\sqrt3cos(x) +sin(x)}} - \frac{1}{\sqrt3}})
\lim_{h\rightarrow0} \frac{1}{h}} (\frac{2sin(x)}{3cos(x) + \sqrt3sin(x)})
Wow, that latex is hard to code... I think I have it now though.
This is asfar as I can go with this problem, from here, I am confused.
allistair
Oct30-04, 05:39 PM
you're making it way to diffcult, lim(h->0) 1/h * (tan(Pi/6 + h)-1/sqrt(3)) is also lim(h->0) 1/h * (tan(Pi/6 + h)-tan(Pi/6)), lim(h->0) 1/h * f(a+h)-f(a) is the differential of f in a, so you really just need to calculate tan's differential in Pi/6
toosm:)ey
Oct30-04, 07:30 PM
Okay, that makes sense and therefore:
\lim_{h\rightarrow0^+} \frac{1}{h}} (\tan(h+(\pi/6))}- \frac{1}{\sqrt3}})
equals
\lim_{h\rightarrow0^+} \frac{1}{h}} (\tan(h+(\pi/6))}- \tan(\frac{\pi}{6}}))
\frac{d}{dx}}\tan(x) = \sec^2(x)
\sec^2(\frac{\pi}{6}}) = \frac{4}{3}}
and
\lim_{h\rightarrow0^+} \frac{1}{h}} (\tan(h+(\pi/6))}- \frac{1}{\sqrt3}}) = \frac{4}{3}}
Is this true?
allistair
Oct31-04, 04:55 AM
yeah, that's what i meant
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