MHB Finding the Continuous Intervals for a function

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The function f(x) = tan(2x) is continuous everywhere except at its vertical asymptotes. These asymptotes occur at x = (2n + 1)π/4, where n is an integer. The function is undefined when cos(2x) = 0, leading to discontinuities at these points. Therefore, the continuous intervals for f(x) are between these asymptotes. Understanding these intervals is crucial for analyzing the behavior of the tangent function.
cbarker1
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I need some help find some continuous intervals for $f(x)=tan(2x)$. I know there are vertical asympotes when x=pi/4+2*pi*n for positive integers. Thank you for your help.

CBarker1
 
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Cbarker1 said:
I need some help find some continuous intervals for $f(x)=tan(2x)$. I know there are vertical asympotes when x=pi/4+2*pi*n for positive integers. Thank you for your help.

CBarker1

$f(x)=tan(2x)$ is continuous everywhere except the vertical asymptotes. To find the vertical asymptotes,we set the denominator $0$.So,as $tan(2x)=\frac{sin(2x)}{cos(2x)}$,we set $cos(2x)=0 \Rightarrow x=\pm \frac{\pi}{4},\pm \frac{3\pi}{4},...$
Therefore,$tan(2x)$ is continuous everywhere except at $x$,where $x=\frac{n \pi}{4}$,where $n$ odd numbers.
 
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There are probably loads of proofs of this online, but I do not want to cheat. Here is my attempt: Convexity says that $$f(\lambda a + (1-\lambda)b) \leq \lambda f(a) + (1-\lambda) f(b)$$ $$f(b + \lambda(a-b)) \leq f(b) + \lambda (f(a) - f(b))$$ We know from the intermediate value theorem that there exists a ##c \in (b,a)## such that $$\frac{f(a) - f(b)}{a-b} = f'(c).$$ Hence $$f(b + \lambda(a-b)) \leq f(b) + \lambda (a - b) f'(c))$$ $$\frac{f(b + \lambda(a-b)) - f(b)}{\lambda(a-b)}...

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