Width and height of binary tree is $\theta(n)$? we know this definition:
Given a binary tree, Width of a tree is maximum of widths of all levels.
Let us consider the below example tree.
     1
    /  \
   2    3
 /  \     \
4    5     8 
          /  \
         6    7

For the above tree,
width of level 1 is 1,
width of level 2 is 2,
width of level 3 is 3
width of level 4 is 2.
So the maximum width of the tree is 3.
can we have a binary tree with Height $\theta(n)$  and Width  $\theta(n)$
My solution:
is YES. for example a binary tree with one-node: 
     1

am i right?

The answer is no.
the Symbol $\Theta (n)$ is related to Average case for set of (bigger) n. So with one tree you couldn't say the tree with one-node has $\Theta (n)$ in height and width.
