What does number one mean of letter b

Convert the cartesian equation (x 2 + y 2)2 = 4(x 2 - y 2) to a polar equation. choices: r4 = -4r2 r2 = 4cos2θ r2 = 4sin2θ

Refer to interactive solution 17.45 to review a method by which this problem can be solved. the fundamental frequencies of two air columns are the same. column a is open at both ends, while column b is open at only one end. the length of column a is 0.504 m. what is the length of column b?

Noor brought 21 sheets of stickers. she gave 1/3 of a sheet to each of the 45 students at recess. she wants to give teachers 1 1/2 sheets each.