A, kåä»ä¹å¼çæ¶åï¼ fæ¯ä¸ä¸ªæ¦çå¯åº¦å½æ°
â«ï¼ï¼âï¼ï¼âï¼f(x)dx=1
=â«[0ï¼1]kx(1-x)^3dx
=â«[0ï¼1]k(x-3x^2+3x^3-x^4)dx
=k(x^2/2-x^3+3/4x^4-x^5/5)[0,1]
=k(1/3-1+3/4-1/5)
=-k/60
k=-60
B, 对äºæ¤å¼çkï¼æ± Pï¼1/4 <X<1ï¼
â«[1/4ï¼1]-60x(1-x)^3dx
ï¼-60(x^2/2-x^3+3/4x^4-x^5/5)[1/4,1]
èªå·±ç®å§
C, æ±æ¤åå¸çå¹³åå¼
E(x)=â«[0ï¼1]kx^2(1-x)^3dx
ç¶å积åäºã
温馨提示:答案为网友推荐,仅供参考