Attached integral calculator cannot solve

[rombva]

(11-15-2019 11:15 AM)yingwuluo Wrote:  Attached integral calculator cannot solve

numerically: int((x^3*cos(x/2)+1/2)*√(4-X^2),x,-2,2) [shift] [enter] returns 3.14159265359.

symbolically: simplify(subst(int((x^3*cos(x/2)+1/2)*√(4-X^2),x,-2,2), x=2*sin(t))) returns pi.