Question 1133686


Express the complex number in trigonometric form. 
{{{-4}}} 

{{{z=r(cos(alpha)+i*sin(alpha))}}}

{{{-4=a-b*i}}} =>{{{a=-4}}}, {{{b=0}}}

{{{r=sqrt((-4)^2)}}}
{{{r= sqrt(16)}}}
{{{r=4}}} 

{{{z=4* (cos(alpha)+i*sin(alpha))}}}

{{{tan(alpha)=0/-4=0}}}

 the angle of the point on the complex plane is {{{pi}}}.


{{{z = 4 (cos(pi) + i *sin(pi))}}}