What are the components of the vector between the origin and the polar coordinate (7, (3pi)/4)?

1 Answer
Aug 26, 2016

(((-7sqrt2)/2),((7sqrt2)/2))

Explanation:

To convert from color(blue)"polar to cartesian coordinates"

color(orange)"Reminder"

color(red)(|bar(ul(color(white)(a/a)color(black)(x=rcostheta , y=rsintheta)color(white)(a/a)|)))

here r = 7 and theta=(3pi)/4

rArrx=7cos((3pi)/4)" and " y=7sin((3pi)/4)

color(orange)"Reminder"

color(red)(|bar(ul(color(white)(a/a)color(black)(cos((3pi)/4)=-cos(pi/4)" and " sin((3pi)/4)=sin(pi/4))color(white)(a/a)|)))

x=7cos((3pi)/4)=-7cos(pi/4)=-7xx1/sqrt2=(-7sqrt2)/2

and y=7sin((3pi)/4)=7sin(pi/4)=7xx1/sqrt2=(7sqrt2)/2

Thus the components of the vector are (((-7sqrt2)/2),((7sqrt2)/2))