해법
cos3(x)−2sin(x)−0.7=0
해법
x=0.13658…+2πn,x=−2.49372…+2πn
+1
도
x=7.82570…∘+360∘n,x=−142.87998…∘+360∘n솔루션 단계
cos3(x)−2sin(x)−0.7=0
더하다 2sin(x) 양쪽으로cos3(x)−0.7=2sin(x)
양쪽을 제곱(cos3(x)−0.7)2=(2sin(x))2
빼다 (2sin(x))2 양쪽에서(cos3(x)−0.7)2−4sin2(x)=0
삼각성을 사용하여 다시 쓰기
(−0.7+cos3(x))2−4sin2(x)
피타고라스 정체성 사용: cos2(x)+sin2(x)=1sin2(x)=1−cos2(x)=(−0.7+cos3(x))2−4(1−cos2(x))
(−0.7+cos3(x))2−4(1−cos2(x))간소화하다 :cos6(x)+4cos2(x)−1.4cos3(x)−3.51
(−0.7+cos3(x))2−4(1−cos2(x))
(−0.7+cos3(x))2:0.49−1.4cos3(x)+cos6(x)
완벽한 정사각형 공식 적용: (a+b)2=a2+2ab+b2a=−0.7,b=cos3(x)
=(−0.7)2+2(−0.7)cos3(x)+(cos3(x))2
(−0.7)2+2(−0.7)cos3(x)+(cos3(x))2단순화하세요:0.49−1.4cos3(x)+cos6(x)
(−0.7)2+2(−0.7)cos3(x)+(cos3(x))2
괄호 제거: (−a)=−a=(−0.7)2−2⋅0.7cos3(x)+(cos3(x))2
(−0.7)2=0.49
(−0.7)2
지수 규칙 적용: (−a)n=an,이면 n 균등하다(−0.7)2=0.72=0.72
0.72=0.49=0.49
2⋅0.7cos3(x)=1.4cos3(x)
2⋅0.7cos3(x)
숫자를 곱하시오: 2⋅0.7=1.4=1.4cos3(x)
(cos3(x))2=cos6(x)
(cos3(x))2
지수 규칙 적용: (ab)c=abc=cos3⋅2(x)
숫자를 곱하시오: 3⋅2=6=cos6(x)
=0.49−1.4cos3(x)+cos6(x)
=0.49−1.4cos3(x)+cos6(x)
=0.49−1.4cos3(x)+cos6(x)−4(1−cos2(x))
−4(1−cos2(x))확대한다:−4+4cos2(x)
−4(1−cos2(x))
분배 법칙 적용: a(b−c)=ab−aca=−4,b=1,c=cos2(x)=−4⋅1−(−4)cos2(x)
마이너스 플러스 규칙 적용−(−a)=a=−4⋅1+4cos2(x)
숫자를 곱하시오: 4⋅1=4=−4+4cos2(x)
=0.49−1.4cos3(x)+cos6(x)−4+4cos2(x)
0.49−1.4cos3(x)+cos6(x)−4+4cos2(x)단순화하세요:cos6(x)+4cos2(x)−1.4cos3(x)−3.51
0.49−1.4cos3(x)+cos6(x)−4+4cos2(x)
집단적 용어=−1.4cos3(x)+cos6(x)+4cos2(x)+0.49−4
숫자 더하기/ 빼기: 0.49−4=−3.51=cos6(x)+4cos2(x)−1.4cos3(x)−3.51
=cos6(x)+4cos2(x)−1.4cos3(x)−3.51
=cos6(x)+4cos2(x)−1.4cos3(x)−3.51
−3.51+cos6(x)−1.4cos3(x)+4cos2(x)=0
대체로 해결
−3.51+cos6(x)−1.4cos3(x)+4cos2(x)=0
하게: cos(x)=u−3.51+u6−1.4u3+4u2=0
−3.51+u6−1.4u3+4u2=0:u≈0.99068…,u≈−0.79737…
−3.51+u6−1.4u3+4u2=0
양쪽을 곱한 값 100
−3.51+u6−1.4u3+4u2=0
To eliminate decimal points, multiply by 10 for every digit after the decimal pointThere are 2digits to the right of the decimal point, therefore multiply by 100−3.51⋅100+u6⋅100−1.4u3⋅100+4u2⋅100=0⋅100
다듬다−351+100u6−140u3+400u2=0
−351+100u6−140u3+400u2=0
표준 양식으로 작성 anxn+…+a1x+a0=0100u6−140u3+400u2−351=0
다음을 위한 하나의 솔루션 찾기 100u6−140u3+400u2−351=0 뉴턴-랩슨을 이용하여:u≈0.99068…
100u6−140u3+400u2−351=0
뉴턴-랩슨 근사 정의
f(u)=100u6−140u3+400u2−351
f′(u)찾다 :600u5−420u2+800u
dud(100u6−140u3+400u2−351)
합계/차이 규칙 적용: (f±g)′=f′±g′=dud(100u6)−dud(140u3)+dud(400u2)−dud(351)
dud(100u6)=600u5
dud(100u6)
정수를 빼라: (a⋅f)′=a⋅f′=100dud(u6)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=100⋅6u6−1
단순화=600u5
dud(140u3)=420u2
dud(140u3)
정수를 빼라: (a⋅f)′=a⋅f′=140dud(u3)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=140⋅3u3−1
단순화=420u2
dud(400u2)=800u
dud(400u2)
정수를 빼라: (a⋅f)′=a⋅f′=400dud(u2)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=400⋅2u2−1
단순화=800u
dud(351)=0
dud(351)
상수의 도함수: dxd(a)=0=0
=600u5−420u2+800u−0
단순화=600u5−420u2+800u
렛 u0=1계산하다 un+1 까지 Δun+1<0.000001
u1=0.99081…:Δu1=0.00918…
f(u0)=100⋅16−140⋅13+400⋅12−351=9f′(u0)=600⋅15−420⋅12+800⋅1=980u1=0.99081…
Δu1=∣0.99081…−1∣=0.00918…Δu1=0.00918…
u2=0.99068…:Δu2=0.00012…
f(u1)=100⋅0.99081…6−140⋅0.99081…3+400⋅0.99081…2−351=0.12339…f′(u1)=600⋅0.99081…5−420⋅0.99081…2+800⋅0.99081…=953.28231…u2=0.99068…
Δu2=∣0.99068…−0.99081…∣=0.00012…Δu2=0.00012…
u3=0.99068…:Δu3=2.51305E−8
f(u2)=100⋅0.99068…6−140⋅0.99068…3+400⋅0.99068…2−351=0.00002…f′(u2)=600⋅0.99068…5−420⋅0.99068…2+800⋅0.99068…=952.91233…u3=0.99068…
Δu3=∣0.99068…−0.99068…∣=2.51305E−8Δu3=2.51305E−8
u≈0.99068…
긴 나눗셈 적용:u−0.99068…100u6−140u3+400u2−351=100u5+99.06868…u4+98.14604…u3−42.76800…u2+357.63030…u+354.29964…
100u5+99.06868…u4+98.14604…u3−42.76800…u2+357.63030…u+354.29964…≈0
다음을 위한 하나의 솔루션 찾기 100u5+99.06868…u4+98.14604…u3−42.76800…u2+357.63030…u+354.29964…=0 뉴턴-랩슨을 이용하여:u≈−0.79737…
100u5+99.06868…u4+98.14604…u3−42.76800…u2+357.63030…u+354.29964…=0
뉴턴-랩슨 근사 정의
f(u)=100u5+99.06868…u4+98.14604…u3−42.76800…u2+357.63030…u+354.29964…
f′(u)찾다 :500u4+396.27474…u3+294.43813…u2−85.53600…u+357.63030…
dud(100u5+99.06868…u4+98.14604…u3−42.76800…u2+357.63030…u+354.29964…)
합계/차이 규칙 적용: (f±g)′=f′±g′=dud(100u5)+dud(99.06868…u4)+dud(98.14604…u3)−dud(42.76800…u2)+dud(357.63030…u)+dud(354.29964…)
dud(100u5)=500u4
dud(100u5)
정수를 빼라: (a⋅f)′=a⋅f′=100dud(u5)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=100⋅5u5−1
단순화=500u4
dud(99.06868…u4)=396.27474…u3
dud(99.06868…u4)
정수를 빼라: (a⋅f)′=a⋅f′=99.06868…dud(u4)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=99.06868…⋅4u4−1
단순화=396.27474…u3
dud(98.14604…u3)=294.43813…u2
dud(98.14604…u3)
정수를 빼라: (a⋅f)′=a⋅f′=98.14604…dud(u3)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=98.14604…⋅3u3−1
단순화=294.43813…u2
dud(42.76800…u2)=85.53600…u
dud(42.76800…u2)
정수를 빼라: (a⋅f)′=a⋅f′=42.76800…dud(u2)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=42.76800…⋅2u2−1
단순화=85.53600…u
dud(357.63030…u)=357.63030…
dud(357.63030…u)
정수를 빼라: (a⋅f)′=a⋅f′=357.63030…dudu
공통 도함수 적용: dudu=1=357.63030…⋅1
단순화=357.63030…
dud(354.29964…)=0
dud(354.29964…)
상수의 도함수: dxd(a)=0=0
=500u4+396.27474…u3+294.43813…u2−85.53600…u+357.63030…+0
단순화=500u4+396.27474…u3+294.43813…u2−85.53600…u+357.63030…
렛 u0=−1계산하다 un+1 까지 Δun+1<0.000001
u1=−0.82744…:Δu1=0.17255…
f(u0)=100(−1)5+99.06868…(−1)4+98.14604…(−1)3−42.76800…(−1)2+357.63030…(−1)+354.29964…=−145.17602…f′(u0)=500(−1)4+396.27474…(−1)3+294.43813…(−1)2−85.53600…(−1)+357.63030…=841.32969…u1=−0.82744…
Δu1=∣−0.82744…−(−1)∣=0.17255…Δu1=0.17255…
u2=−0.79798…:Δu2=0.02946…
f(u1)=100(−0.82744…)5+99.06868…(−0.82744…)4+98.14604…(−0.82744…)3−42.76800…(−0.82744…)2+357.63030…(−0.82744…)+354.29964…=−18.85098…f′(u1)=500(−0.82744…)4+396.27474…(−0.82744…)3+294.43813…(−0.82744…)2−85.53600…(−0.82744…)+357.63030…=639.88234…u2=−0.79798…
Δu2=∣−0.79798…−(−0.82744…)∣=0.02946…Δu2=0.02946…
u3=−0.79737…:Δu3=0.00061…
f(u2)=100(−0.79798…)5+99.06868…(−0.79798…)4+98.14604…(−0.79798…)3−42.76800…(−0.79798…)2+357.63030…(−0.79798…)+354.29964…=−0.37564…f′(u2)=500(−0.79798…)4+396.27474…(−0.79798…)3+294.43813…(−0.79798…)2−85.53600…(−0.79798…)+357.63030…=614.75965…u3=−0.79737…
Δu3=∣−0.79737…−(−0.79798…)∣=0.00061…Δu3=0.00061…
u4=−0.79737…:Δu4=2.47446E−7
f(u3)=100(−0.79737…)5+99.06868…(−0.79737…)4+98.14604…(−0.79737…)3−42.76800…(−0.79737…)2+357.63030…(−0.79737…)+354.29964…=−0.00015…f′(u3)=500(−0.79737…)4+396.27474…(−0.79737…)3+294.43813…(−0.79737…)2−85.53600…(−0.79737…)+357.63030…=614.26230…u4=−0.79737…
Δu4=∣−0.79737…−(−0.79737…)∣=2.47446E−7Δu4=2.47446E−7
u≈−0.79737…
긴 나눗셈 적용:u+0.79737…100u5+99.06868…u4+98.14604…u3−42.76800…u2+357.63030…u+354.29964…=100u4+19.33136…u3+82.73173…u2−108.73606…u+444.33352…
100u4+19.33136…u3+82.73173…u2−108.73606…u+444.33352…≈0
다음을 위한 하나의 솔루션 찾기 100u4+19.33136…u3+82.73173…u2−108.73606…u+444.33352…=0 뉴턴-랩슨을 이용하여:솔루션 없음 u∈R
100u4+19.33136…u3+82.73173…u2−108.73606…u+444.33352…=0
뉴턴-랩슨 근사 정의
f(u)=100u4+19.33136…u3+82.73173…u2−108.73606…u+444.33352…
f′(u)찾다 :400u3+57.99410…u2+165.46346…u−108.73606…
dud(100u4+19.33136…u3+82.73173…u2−108.73606…u+444.33352…)
합계/차이 규칙 적용: (f±g)′=f′±g′=dud(100u4)+dud(19.33136…u3)+dud(82.73173…u2)−dud(108.73606…u)+dud(444.33352…)
dud(100u4)=400u3
dud(100u4)
정수를 빼라: (a⋅f)′=a⋅f′=100dud(u4)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=100⋅4u4−1
단순화=400u3
dud(19.33136…u3)=57.99410…u2
dud(19.33136…u3)
정수를 빼라: (a⋅f)′=a⋅f′=19.33136…dud(u3)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=19.33136…⋅3u3−1
단순화=57.99410…u2
dud(82.73173…u2)=165.46346…u
dud(82.73173…u2)
정수를 빼라: (a⋅f)′=a⋅f′=82.73173…dud(u2)
전원 규칙을 적용합니다: dxd(xa)=a⋅xa−1=82.73173…⋅2u2−1
단순화=165.46346…u
dud(108.73606…u)=108.73606…
dud(108.73606…u)
정수를 빼라: (a⋅f)′=a⋅f′=108.73606…dudu
공통 도함수 적용: dudu=1=108.73606…⋅1
단순화=108.73606…
dud(444.33352…)=0
dud(444.33352…)
상수의 도함수: dxd(a)=0=0
=400u3+57.99410…u2+165.46346…u−108.73606…+0
단순화=400u3+57.99410…u2+165.46346…u−108.73606…
렛 u0=4계산하다 un+1 까지 Δun+1<0.000001
u1=2.95977…:Δu1=1.04022…
f(u0)=100⋅44+19.33136…⋅43+82.73173…⋅42−108.73606…⋅4+444.33352…=28170.30446…f′(u0)=400⋅43+57.99410…⋅42+165.46346…⋅4−108.73606…=27081.02341…u1=2.95977…
Δu1=∣2.95977…−4∣=1.04022…Δu1=1.04022…
u2=2.15849…:Δu2=0.80127…
f(u1)=100⋅2.95977…4+19.33136…⋅2.95977…3+82.73173…⋅2.95977…2−108.73606…⋅2.95977…+444.33352…=9022.73494…f′(u1)=400⋅2.95977…3+57.99410…⋅2.95977…2+165.46346…⋅2.95977…−108.73606…=11260.43299…u2=2.15849…
Δu2=∣2.15849…−2.95977…∣=0.80127…Δu2=0.80127…
u3=1.50665…:Δu3=0.65184…
f(u2)=100⋅2.15849…4+19.33136…⋅2.15849…3+82.73173…⋅2.15849…2−108.73606…⋅2.15849…+444.33352…=2960.23225…f′(u2)=400⋅2.15849…3+57.99410…⋅2.15849…2+165.46346…⋅2.15849…−108.73606…=4541.29955…u3=1.50665…
Δu3=∣1.50665…−2.15849…∣=0.65184…Δu3=0.65184…
u4=0.86667…:Δu4=0.63997…
f(u3)=100⋅1.50665…4+19.33136…⋅1.50665…3+82.73173…⋅1.50665…2−108.73606…⋅1.50665…+444.33352…=1049.71285…f′(u3)=400⋅1.50665…3+57.99410…⋅1.50665…2+165.46346…⋅1.50665…−108.73606…=1640.24724…u4=0.86667…
Δu4=∣0.86667…−1.50665…∣=0.63997…Δu4=0.63997…
u5=−0.55447…:Δu5=1.42115…
f(u4)=100⋅0.86667…4+19.33136…⋅0.86667…3+82.73173…⋅0.86667…2−108.73606…⋅0.86667…+444.33352…=481.24159…f′(u4)=400⋅0.86667…3+57.99410…⋅0.86667…2+165.46346…⋅0.86667…−108.73606…=338.62623…u5=−0.55447…
Δu5=∣−0.55447…−0.86667…∣=1.42115…Δu5=1.42115…
u6=1.58320…:Δu6=2.13768…
f(u5)=100(−0.55447…)4+19.33136…(−0.55447…)3+82.73173…(−0.55447…)2−108.73606…(−0.55447…)+444.33352…=536.21783…f′(u5)=400(−0.55447…)3+57.99410…(−0.55447…)2+165.46346…(−0.55447…)−108.73606…=−250.84100…u6=1.58320…
Δu6=∣1.58320…−(−0.55447…)∣=2.13768…Δu6=2.13768…
u7=0.95511…:Δu7=0.62809…
f(u6)=100⋅1.58320…4+19.33136…⋅1.58320…3+82.73173…⋅1.58320…2−108.73606…⋅1.58320…+444.33352…=1184.53262…f′(u6)=400⋅1.58320…3+57.99410…⋅1.58320…2+165.46346…⋅1.58320…−108.73606…=1885.92418…u7=0.95511…
Δu7=∣0.95511…−1.58320…∣=0.62809…Δu7=0.62809…
u8=−0.18975…:Δu8=1.14486…
f(u7)=100⋅0.95511…4+19.33136…⋅0.95511…3+82.73173…⋅0.95511…2−108.73606…⋅0.95511…+444.33352…=516.00984…f′(u7)=400⋅0.95511…3+57.99410…⋅0.95511…2+165.46346…⋅0.95511…−108.73606…=450.71799…u8=−0.18975…
Δu8=∣−0.18975…−0.95511…∣=1.14486…Δu8=1.14486…
u9=3.13422…:Δu9=3.32398…
f(u8)=100(−0.18975…)4+19.33136…(−0.18975…)3+82.73173…(−0.18975…)2−108.73606…(−0.18975…)+444.33352…=467.94277…f′(u8)=400(−0.18975…)3+57.99410…(−0.18975…)2+165.46346…(−0.18975…)−108.73606…=−140.77780…u9=3.13422…
Δu9=∣3.13422…−(−0.18975…)∣=3.32398…Δu9=3.32398…
해결 방법을 찾을 수 없습니다
해결책은u≈0.99068…,u≈−0.79737…
뒤로 대체 u=cos(x)cos(x)≈0.99068…,cos(x)≈−0.79737…
cos(x)≈0.99068…,cos(x)≈−0.79737…
cos(x)=0.99068…:x=arccos(0.99068…)+2πn,x=2π−arccos(0.99068…)+2πn
cos(x)=0.99068…
트리거 역속성 적용
cos(x)=0.99068…
일반 솔루션 cos(x)=0.99068…cos(x)=a⇒x=arccos(a)+2πn,x=2π−arccos(a)+2πnx=arccos(0.99068…)+2πn,x=2π−arccos(0.99068…)+2πn
x=arccos(0.99068…)+2πn,x=2π−arccos(0.99068…)+2πn
cos(x)=−0.79737…:x=arccos(−0.79737…)+2πn,x=−arccos(−0.79737…)+2πn
cos(x)=−0.79737…
트리거 역속성 적용
cos(x)=−0.79737…
일반 솔루션 cos(x)=−0.79737…cos(x)=−a⇒x=arccos(−a)+2πn,x=−arccos(−a)+2πnx=arccos(−0.79737…)+2πn,x=−arccos(−0.79737…)+2πn
x=arccos(−0.79737…)+2πn,x=−arccos(−0.79737…)+2πn
모든 솔루션 결합x=arccos(0.99068…)+2πn,x=2π−arccos(0.99068…)+2πn,x=arccos(−0.79737…)+2πn,x=−arccos(−0.79737…)+2πn
해법을 원래 방정식에 연결하여 검증
솔루션을 에 연결하여 확인합니다 cos3(x)−2sin(x)−0.7=0
방정식에 맞지 않는 것은 제거하십시오.
솔루션 확인 arccos(0.99068…)+2πn:참
arccos(0.99068…)+2πn
n=1끼우다 arccos(0.99068…)+2π1
cos3(x)−2sin(x)−0.7=0 위한 {\ quad}끼우다{\ quad} x=arccos(0.99068…)+2π1cos3(arccos(0.99068…)+2π1)−2sin(arccos(0.99068…)+2π1)−0.7=0
다듬다0=0
⇒참
솔루션 확인 2π−arccos(0.99068…)+2πn:거짓
2π−arccos(0.99068…)+2πn
n=1끼우다 2π−arccos(0.99068…)+2π1
cos3(x)−2sin(x)−0.7=0 위한 {\ quad}끼우다{\ quad} x=2π−arccos(0.99068…)+2π1cos3(2π−arccos(0.99068…)+2π1)−2sin(2π−arccos(0.99068…)+2π1)−0.7=0
다듬다0.54463…=0
⇒거짓
솔루션 확인 arccos(−0.79737…)+2πn:거짓
arccos(−0.79737…)+2πn
n=1끼우다 arccos(−0.79737…)+2π1
cos3(x)−2sin(x)−0.7=0 위한 {\ quad}끼우다{\ quad} x=arccos(−0.79737…)+2π1cos3(arccos(−0.79737…)+2π1)−2sin(arccos(−0.79737…)+2π1)−0.7=0
다듬다−2.41394…=0
⇒거짓
솔루션 확인 −arccos(−0.79737…)+2πn:참
−arccos(−0.79737…)+2πn
n=1끼우다 −arccos(−0.79737…)+2π1
cos3(x)−2sin(x)−0.7=0 위한 {\ quad}끼우다{\ quad} x=−arccos(−0.79737…)+2π1cos3(−arccos(−0.79737…)+2π1)−2sin(−arccos(−0.79737…)+2π1)−0.7=0
다듬다0=0
⇒참
x=arccos(0.99068…)+2πn,x=−arccos(−0.79737…)+2πn
해를 10진수 형식으로 표시x=0.13658…+2πn,x=−2.49372…+2πn