Taking the origin of rectangular coordinates as the pole and the positive direction of X axis as the polar axis, it is relevant when establishing polar coordinate system.
x =ρ* cosθ; y=ρ*sinθ,
The elliptic equation is transformed into:
(ρ*cosθ)? /a? + (ρ*sinθ)? /b? = 1
Let the coordinates of point A be a (ρ 1, θ1); The coordinate of point b is b (ρ 2, θ 2);
* oa⊥ob
∴θ2 =θ 1π/2 = = & gt; Because? θ2 = sin? θ 1; Sin? θ2 = cos? θ 1;
A and b are points on the ellipse, so there are:
(ρ 1*cosθ 1)? /a? + (ρ 1*sinθ 1)? /b? = 1
= = & gtρ 1? = a? b? /(a? Sin? θ 1 + b? Because? θ 1) - ( 1)
(ρ2*cosθ2)? /a? + (ρ2*sinθ2)? /b? = 1
= = & gtρ2? = a? b? /(a? Sin? θ2 + b? Because? θ2)
= a? b? /(a? Because? θ + b? Sin? θ 1) - (2)
sδAOB = 1/2 * | OA | * | OB |
= 1/2 *ρ 1*ρ2
= 1/2 *√[a? b? /(a? Sin? θ 1 + b? Because? θ 1)] * √[a? b? /(a? Sin? θ 1 + b? Because? θ 1)]
= a? b? /√[4a? b? +sin? (2*θ 1)*(a? -B? )? ]
As a crime? When (2*θ 1) = 1, the triangle area has a minimum value.
Minimum value = a? b? /√[4a? b? + 1/4*(a? -B? )? ] = a? b? /(a? + b? )
As a crime? When (2*θ 1) = 0, the triangle area has a maximum value.
Maximum value = a? b? /√(4a? b? )= ab/2