해법
tan(x)=2+tan3(x)
해법
x=−0.98930…+πn
+1
도
x=−56.68315…∘+180∘n솔루션 단계
tan(x)=2+tan3(x)
대체로 해결
tan(x)=2+tan3(x)
하게: tan(x)=uu=2+u3
u=2+u3:u≈−1.52137…
u=2+u3
측면 전환2+u3=u
u를 왼쪽으로 이동
2+u3=u
빼다 u 양쪽에서2+u3−u=u−u
단순화2+u3−u=0
2+u3−u=0
표준 양식으로 작성 anxn+…+a1x+a0=0u3−u+2=0
다음을 위한 하나의 솔루션 찾기 u3−u+2=0 뉴턴-랩슨을 이용하여:u≈−1.52137…
u3−u+2=0
뉴턴-랩슨 근사 정의
f(u)=u3−u+2
f′(u)찾다 :3u2−1
dud(u3−u+2)
합계/차이 규칙 적용: (f±g)′=f′±g′=dud(u3)−dudu+dud(2)
dud(u3)=3u2
dud(u3)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=3u3−1
단순화=3u2
dudu=1
dudu
공통 도함수 적용: dudu=1=1
dud(2)=0
dud(2)
상수의 도함수: dxd(a)=0=0
=3u2−1+0
단순화=3u2−1
렛 u0=−1계산하다 un+1 까지 Δun+1<0.000001
u1=−2:Δu1=1
f(u0)=(−1)3−(−1)+2=2f′(u0)=3(−1)2−1=2u1=−2
Δu1=∣−2−(−1)∣=1Δu1=1
u2=−1.63636…:Δu2=0.36363…
f(u1)=(−2)3−(−2)+2=−4f′(u1)=3(−2)2−1=11u2=−1.63636…
Δu2=∣−1.63636…−(−2)∣=0.36363…Δu2=0.36363…
u3=−1.53039…:Δu3=0.10597…
f(u2)=(−1.63636…)3−(−1.63636…)+2=−0.74530…f′(u2)=3(−1.63636…)2−1=7.03305…u3=−1.53039…
Δu3=∣−1.53039…−(−1.63636…)∣=0.10597…Δu3=0.10597…
u4=−1.52144…:Δu4=0.00895…
f(u3)=(−1.53039…)3−(−1.53039…)+2=−0.05393…f′(u3)=3(−1.53039…)2−1=6.02629…u4=−1.52144…
Δu4=∣−1.52144…−(−1.53039…)∣=0.00895…Δu4=0.00895…
u5=−1.52137…:Δu5=0.00006…
f(u4)=(−1.52144…)3−(−1.52144…)+2=−0.00036…f′(u4)=3(−1.52144…)2−1=5.94435…u5=−1.52137…
Δu5=∣−1.52137…−(−1.52144…)∣=0.00006…Δu5=0.00006…
u6=−1.52137…:Δu6=2.92858E−9
f(u5)=(−1.52137…)3−(−1.52137…)+2=−1.74069E−8f′(u5)=3(−1.52137…)2−1=5.94378…u6=−1.52137…
Δu6=∣−1.52137…−(−1.52137…)∣=2.92858E−9Δu6=2.92858E−9
u≈−1.52137…
긴 나눗셈 적용:u+1.52137…u3−u+2=u2−1.52137…u+1.31459…
u2−1.52137…u+1.31459…≈0
다음을 위한 하나의 솔루션 찾기 u2−1.52137…u+1.31459…=0 뉴턴-랩슨을 이용하여:솔루션 없음 u∈R
u2−1.52137…u+1.31459…=0
뉴턴-랩슨 근사 정의
f(u)=u2−1.52137…u+1.31459…
f′(u)찾다 :2u−1.52137…
dud(u2−1.52137…u+1.31459…)
합계/차이 규칙 적용: (f±g)′=f′±g′=dud(u2)−dud(1.52137…u)+dud(1.31459…)
dud(u2)=2u
dud(u2)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=2u2−1
단순화=2u
dud(1.52137…u)=1.52137…
dud(1.52137…u)
정수를 빼라: (a⋅f)′=a⋅f′=1.52137…dudu
공통 도함수 적용: dudu=1=1.52137…⋅1
단순화=1.52137…
dud(1.31459…)=0
dud(1.31459…)
상수의 도함수: dxd(a)=0=0
=2u−1.52137…+0
단순화=2u−1.52137…
렛 u0=1계산하다 un+1 까지 Δun+1<0.000001
u1=−0.65729…:Δu1=1.65729…
f(u0)=12−1.52137…⋅1+1.31459…=0.79321…f′(u0)=2⋅1−1.52137…=0.47862…u1=−0.65729…
Δu1=∣−0.65729…−1∣=1.65729…Δu1=1.65729…
u2=0.31119…:Δu2=0.96849…
f(u1)=(−0.65729…)2−1.52137…(−0.65729…)+1.31459…=2.74663…f′(u1)=2(−0.65729…)−1.52137…=−2.83597…u2=0.31119…
Δu2=∣0.31119…−(−0.65729…)∣=0.96849…Δu2=0.96849…
u3=1.35459…:Δu3=1.04339…
f(u2)=0.31119…2−1.52137…⋅0.31119…+1.31459…=0.93798…f′(u2)=2⋅0.31119…−1.52137…=−0.89897…u3=1.35459…
Δu3=∣1.35459…−0.31119…∣=1.04339…Δu3=1.04339…
u4=0.43805…:Δu4=0.91653…
f(u3)=1.35459…2−1.52137…⋅1.35459…+1.31459…=1.08866…f′(u3)=2⋅1.35459…−1.52137…=1.18780…u4=0.43805…
Δu4=∣0.43805…−1.35459…∣=0.91653…Δu4=0.91653…
u5=1.73989…:Δu5=1.30184…
f(u4)=0.43805…2−1.52137…⋅0.43805…+1.31459…=0.84004…f′(u4)=2⋅0.43805…−1.52137…=−0.64527…u5=1.73989…
Δu5=∣1.73989…−0.43805…∣=1.30184…Δu5=1.30184…
u6=0.87450…:Δu6=0.86539…
f(u5)=1.73989…2−1.52137…⋅1.73989…+1.31459…=1.69479…f′(u5)=2⋅1.73989…−1.52137…=1.95841…u6=0.87450…
Δu6=∣0.87450…−1.73989…∣=0.86539…Δu6=0.86539…
u7=−2.41546…:Δu7=3.28996…
f(u6)=0.87450…2−1.52137…⋅0.87450…+1.31459…=0.74890…f′(u6)=2⋅0.87450…−1.52137…=0.22763…u7=−2.41546…
Δu7=∣−2.41546…−0.87450…∣=3.28996…Δu7=3.28996…
u8=−0.71153…:Δu8=1.70393…
f(u7)=(−2.41546…)2−1.52137…(−2.41546…)+1.31459…=10.82387…f′(u7)=2(−2.41546…)−1.52137…=−6.35230…u8=−0.71153…
Δu8=∣−0.71153…−(−2.41546…)∣=1.70393…Δu8=1.70393…
u9=0.27452…:Δu9=0.98605…
f(u8)=(−0.71153…)2−1.52137…(−0.71153…)+1.31459…=2.90337…f′(u8)=2(−0.71153…)−1.52137…=−2.94443…u9=0.27452…
Δu9=∣0.27452…−(−0.71153…)∣=0.98605…Δu9=0.98605…
u10=1.27449…:Δu10=0.99997…
f(u9)=0.27452…2−1.52137…⋅0.27452…+1.31459…=0.97230…f′(u9)=2⋅0.27452…−1.52137…=−0.97233…u10=1.27449…
Δu10=∣1.27449…−0.27452…∣=0.99997…Δu10=0.99997…
해결 방법을 찾을 수 없습니다
해결책은u≈−1.52137…
뒤로 대체 u=tan(x)tan(x)≈−1.52137…
tan(x)≈−1.52137…
tan(x)=−1.52137…:x=arctan(−1.52137…)+πn
tan(x)=−1.52137…
트리거 역속성 적용
tan(x)=−1.52137…
일반 솔루션 tan(x)=−1.52137…tan(x)=−a⇒x=arctan(−a)+πnx=arctan(−1.52137…)+πn
x=arctan(−1.52137…)+πn
모든 솔루션 결합x=arctan(−1.52137…)+πn
해를 10진수 형식으로 표시x=−0.98930…+πn