Question

(Q3) Find the values of e, a, b, and c for r = 21/ 5 - 2 cos theta

Answer 1

Choice C

e = 2/5

a = 5

c = 2

Answer 2

Choice C

e = 2/5

a = 5

c = 2

`b=√(21)`

Explanation:

The first step is to write the polar equation in standard form by dividing the numerator and denominator by 5;

`r=((21)/(5) )/(1-(2)/(5)cos(theta) )`

The eccentricity is the coefficient of cos theta, thus

e = 2/5

By definition;

e = c/a

Thus;

c = 2

a = 5

Finally;

`b^(2)=a^(2)-c^(2) \\b^(2)=25-4\\ b=√(21)`