`4` Write the trigonometric form of the number.

To convert 4 to trigonometric form, express it in z=x+yi form. So it becomes:

`z=4+0i`

Take note that the trigonometric form of a complex number z=x+yi is

`z=r(cos theta + isin theta )`

where 

`r= sqrt(x^2+y^2)`     and     `theta = tan^(-1) y/x`

Applying these two formulas, the values of r and theta of z=4+0i are:

`r=sqrt(4^2+0^2)=4`

`theta = tan^(-1) 0/4 =0^o`

Plugging them to the trigonometric form of a complex number result to:

`z= 4(cos0^o + isin 0^o)`

Therefore, the trigonometric form of 4 is  `4(cos 0^o + isin 0^o)` .