化简
极坐标参数方程：a=2arctan(7tan(t/2)) r=24/7-3/(4-3cos(t)) 能不能消除t r(a)能不能化简，是什么曲线 $r=\frac{3}{4+3cos2a}$ 本帖最后由 northwolves 于 2021-2-4 23:37 编辑$a=2arctan(7tan(t/2))$--->$tan(t/2)=1/7tan(a/2)$--->$cost=\frac{1-tan^2 \frac{t}{2}){1+tan^2\frac{t}{2}}=\frac{49-tan^2 \frac{a}{2}){49+tan^2\frac{a}{2}}$
$r=24/7-3/(4-3cos(t)) =24/7-3/(4-3\frac{49-tan^2 \frac{a}{2}){49+tan^2\frac{a}{2}})=24/7-\frac {3(49+tan^2\frac{a}{2}) }{49+7tan^2 \frac{a}{2}} $
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