trigonometric angle tangent identity, a and b are equivalent? I have a question about trigonometric angle identities. 

if $\tan(a)=\cot(b)$

can I say $a=b$?

$a$ and $b$ are in rads respectively. Thanks for your help.
Then: $\dfrac{sina}{cosa} = \dfrac{cosb}{sinb} \to cosa\cdot cosb - sina\cdot sinb = 0 \to cos(a+b) = 0 \to a+b = (2n+1)\cdot \dfrac{\pi}{2}$, $n \in \mathbb{Z}$
No probably not as -
$$tan (a) = cot (b)$$
$$\implies tan (a) = 1/tan(b)$$
$$\implies tan (a) tan(b)=1 $$
$$\implies 1-tan(a)tan(b)=0 ...\alpha$$ 
Now 
$$\begin{align}
\tan(a+b)&amp;=\frac{tan(a)+tan(b)}{1-tan(a) tan(b)}\\\end{align}$$
But from $\alpha$ we have
$$1-tan(a)tan(b)=0$$
$$\implies tan(a+b)=\infty$$
$$\implies a+b=arctan\infty$$
$$\implies a+b=90$$
$$\implies a=90-b$$
So if $$tan(a)=cot(b)$$,then $$a=90-b$$