해법
∫4x2+1x4dx
해법
8(2563lntan(21arctan(x))+1−256(tan(21arctan(x))+1)3+256(tan(21arctan(x))+1)21+64(tan(21arctan(x))+1)31−128(tan(21arctan(x))+1)41−2563lntan(21arctan(x))−1−256(tan(21arctan(x))−1)3−256(tan(21arctan(x))−1)21+64(tan(21arctan(x))−1)31+128(tan(21arctan(x))−1)41)+C
솔루션 단계
∫4x2+1x4dx
정수를 빼라: ∫a⋅f(x)dx=a⋅∫f(x)dx=41⋅∫x2+1x4dx
삼각형 대체 적용
=41⋅∫tan4(u)sec(u)du
삼각성을 사용하여 다시 쓰기
=41⋅∫cos5(u)sin4(u)du
대체 적용
=41⋅∫(1−v2)532v4dv
정수를 빼라: ∫a⋅f(x)dx=a⋅∫f(x)dx=41⋅32⋅∫(1−v2)5v4dv
(1−v2)5v4의 부분적인 부분을 취하라:256(v+1)3+256(v+1)23−128(v+1)31−64(v+1)43+32(v+1)51−256(v−1)3+256(v−1)23+128(v−1)31−64(v−1)43−32(v−1)51
=41⋅32⋅∫256(v+1)3+256(v+1)23−128(v+1)31−64(v+1)43+32(v+1)51−256(v−1)3+256(v−1)23+128(v−1)31−64(v−1)43−32(v−1)51dv
합계 규칙 적용: ∫f(x)±g(x)dx=∫f(x)dx±∫g(x)dx=41⋅32(∫256(v+1)3dv+∫256(v+1)23dv−∫128(v+1)31dv−∫64(v+1)43dv+∫32(v+1)51dv−∫256(v−1)3dv+∫256(v−1)23dv+∫128(v−1)31dv−∫64(v−1)43dv−∫32(v−1)51dv)
∫256(v+1)3dv=2563ln∣v+1∣
∫256(v+1)23dv=−256(v+1)3
∫128(v+1)31dv=−256(v+1)21
∫64(v+1)43dv=−64(v+1)31
∫32(v+1)51dv=−128(v+1)41
∫256(v−1)3dv=2563ln∣v−1∣
∫256(v−1)23dv=−256(v−1)3
∫128(v−1)31dv=−256(v−1)21
∫64(v−1)43dv=−64(v−1)31
∫32(v−1)51dv=−128(v−1)41
=41⋅32(2563ln∣v+1∣−256(v+1)3−(−256(v+1)21)−(−64(v+1)31)−128(v+1)41−2563ln∣v−1∣−256(v−1)3−256(v−1)21−(−64(v−1)31)−(−128(v−1)41))
뒤로 대체
=41⋅322563lntan(2arctan(x))+1−256(tan(2arctan(x))+1)3−−256(tan(2arctan(x))+1)21−−64(tan(2arctan(x))+1)31−128(tan(2arctan(x))+1)41−2563lntan(2arctan(x))−1−256(tan(2arctan(x))−1)3−256(tan(2arctan(x))−1)21−−64(tan(2arctan(x))−1)31−−128(tan(2arctan(x))−1)41
41⋅322563lntan(2arctan(x))+1−256(tan(2arctan(x))+1)3−−256(tan(2arctan(x))+1)21−−64(tan(2arctan(x))+1)31−128(tan(2arctan(x))+1)41−2563lntan(2arctan(x))−1−256(tan(2arctan(x))−1)3−256(tan(2arctan(x))−1)21−−64(tan(2arctan(x))−1)31−−128(tan(2arctan(x))−1)41간소화하다 :8(2563lntan(21arctan(x))+1−256(tan(21arctan(x))+1)3+256(tan(21arctan(x))+1)21+64(tan(21arctan(x))+1)31−128(tan(21arctan(x))+1)41−2563lntan(21arctan(x))−1−256(tan(21arctan(x))−1)3−256(tan(21arctan(x))−1)21+64(tan(21arctan(x))−1)31+128(tan(21arctan(x))−1)41)
=8(2563lntan(21arctan(x))+1−256(tan(21arctan(x))+1)3+256(tan(21arctan(x))+1)21+64(tan(21arctan(x))+1)31−128(tan(21arctan(x))+1)41−2563lntan(21arctan(x))−1−256(tan(21arctan(x))−1)3−256(tan(21arctan(x))−1)21+64(tan(21arctan(x))−1)31+128(tan(21arctan(x))−1)41)
솔루션에 상수 추가=8(2563lntan(21arctan(x))+1−256(tan(21arctan(x))+1)3+256(tan(21arctan(x))+1)21+64(tan(21arctan(x))+1)31−128(tan(21arctan(x))+1)41−2563lntan(21arctan(x))−1−256(tan(21arctan(x))−1)3−256(tan(21arctan(x))−1)21+64(tan(21arctan(x))−1)31+128(tan(21arctan(x))−1)41)+C