Find the distance between the points with polar coordinates (2, pi /3) and (4, 2pi /3).
1 Answers
Best Answer
Recall that:
D=sqrt(r_(1)^(2)+r_(2)^(2)-2r_(1)r_(2)cos (0_(1)-0_(2)))
The proof is given in the next exercise
D=sqrt(2^(2)+4^(2)-2*2*4cos ((pi)/(3)-(2pi)/(3)))
D=sqrt(20-16cos (-(pi)/(3)))
D=sqrt(20-16*(1)/(2))
D=sqrt(20-8)=sqrt(12)=2sqrt(3)
Result:
D=2sqrt(3)