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))#