a\in\langle-1,1\rangle \wedge b\in(-\frac{\pi}{2},\frac{\pi}{2})

b\in\langle-1,1\rangle \wedge a\in\langle 0,\pi\rangle

b\in\langle-1,1\rangle \wedge a\in(-\frac{\pi}{2},\frac{\pi}{2})

b\in\langle-1,1\rangle \wedge a\in\langle-\frac{\pi}{2},\frac{\pi}{2}\rangle

a\in\langle-1,1\rangle \wedge b\in\langle-\frac{\pi}{2},\frac{\pi}{2}\rangle

a\in\mathbb{R} \wedge b\in(-\frac{\pi}{2},\frac{\pi}{2})

b\in\mathbb{R} \wedge  a\in(0,\pi)

b\in\mathbb{R} \wedge a\in(-\frac{\pi}{2},\frac{\pi}{2})

a\in\langle-1,1\rangle \wedge b\in\langle 0,\pi\rangle

a\in\mathbb{R} \wedge b\in(0,\pi)

a_n=\ln(1-n)

a_n=(-1)^n

a_n=\arctan n

\lim_{h\to 0}\frac{f(a-h)-f(a)}{h}

\lim_{h\to 0}\frac{f(a+h)-f(a)}{h}

\lim_{x\to x_0}\frac{f(x)-f(x_0)}{x-x_0}

\lim_{x\to a}\frac{f(a)-f(x)}{x-a}

f(x)=\arctan x

f(x)=\tan x

f(x)=\arcsin x

3(\sin(-2)+i\cos(-2))

3(\cos(-2)+i\sin(-2))

3(\cos 2-i\sin2 )

2(\cos 3-i\sin 3)

f(x)=\ln x

f(x)=\frac{\sin x}{x}

f(x)=\arctan\frac{1}{x}

f(x)=\frac{1}{e^x}