題目 Problem Part III Solve the following problems Suppose that f(t)f(t)f(t) is a continuous function on [0,∞)[0,\infty)[0,∞) satisfying f(t)=eπt2+∬x2+y2≤t2f(x2+y2) dA.f(t)=e^{\pi t^2}+\iint_{x^2+y^2\le t^2}f\left(\sqrt{x^2+y^2}\right)\,\mathrm{d}A.f(t)=eπt2+∬x2+y2≤t2f(x2+y2)dA. Find f(t)f(t)f(t). 解答
