tinh tich phan tu pi/4 den pi/2 cua sin^4x/(sin^4x+cos^4x)



to lam ra pi/8-(1/4canbachaicua2)*ln(3-2canbachaicua2) nhung k pit dung or sai cac pan jup minh nha


pan nao lam dc xin gui wa yahoo meocon164@ymail.com cho minh cung dc