解
9.8⋅sin(α)−0.2⋅9.8⋅cos(α)=0.47
解
α=−2.99124…+2πn,α=0.24444…+2πn
+1
度
α=−171.38555…∘+360∘n,α=14.00542…∘+360∘n解答ステップ
9.8sin(α)−0.2⋅9.8cos(α)=0.47
両辺に0.29.8cos(α)を足す9.8sin(α)=0.47+1.96cos(α)
両辺を2乗する(9.8sin(α))2=(0.47+1.96cos(α))2
両辺から(0.47+1.96cos(α))2を引く96.04sin2(α)−0.2209−1.8424cos(α)−3.8416cos2(α)=0
三角関数の公式を使用して書き換える
−0.2209−1.8424cos(α)−3.8416cos2(α)+96.04sin2(α)
ピタゴラスの公式を使用する: cos2(x)+sin2(x)=1sin2(x)=1−cos2(x)=−0.2209−1.8424cos(α)−3.8416cos2(α)+96.04(1−cos2(α))
簡素化 −0.2209−1.8424cos(α)−3.8416cos2(α)+96.04(1−cos2(α)):−99.8816cos2(α)−1.8424cos(α)+95.8191
−0.2209−1.8424cos(α)−3.8416cos2(α)+96.04(1−cos2(α))
拡張 96.04(1−cos2(α)):96.04−96.04cos2(α)
96.04(1−cos2(α))
分配法則を適用する: a(b−c)=ab−aca=96.04,b=1,c=cos2(α)=96.04⋅1−96.04cos2(α)
=1⋅96.04−96.04cos2(α)
数を乗じる:1⋅96.04=96.04=96.04−96.04cos2(α)
=−0.2209−1.8424cos(α)−3.8416cos2(α)+96.04−96.04cos2(α)
簡素化 −0.2209−1.8424cos(α)−3.8416cos2(α)+96.04−96.04cos2(α):−99.8816cos2(α)−1.8424cos(α)+95.8191
−0.2209−1.8424cos(α)−3.8416cos2(α)+96.04−96.04cos2(α)
条件のようなグループ=−1.8424cos(α)−3.8416cos2(α)−96.04cos2(α)−0.2209+96.04
類似した元を足す:−3.8416cos2(α)−96.04cos2(α)=−99.8816cos2(α)=−1.8424cos(α)−99.8816cos2(α)−0.2209+96.04
数を足す/引く:−0.2209+96.04=95.8191=−99.8816cos2(α)−1.8424cos(α)+95.8191
=−99.8816cos2(α)−1.8424cos(α)+95.8191
=−99.8816cos2(α)−1.8424cos(α)+95.8191
95.8191−1.8424cos(α)−99.8816cos2(α)=0
置換で解く
95.8191−1.8424cos(α)−99.8816cos2(α)=0
仮定:cos(α)=u95.8191−1.8424u−99.8816u2=0
95.8191−1.8424u−99.8816u2=0:u=−199.76321.8424+38285.654512,u=199.763238285.654512−1.8424
95.8191−1.8424u−99.8816u2=0
標準的な形式で書く ax2+bx+c=0−99.8816u2−1.8424u+95.8191=0
解くとthe二次式
−99.8816u2−1.8424u+95.8191=0
二次Equationの公式:
次の場合: a=−99.8816,b=−1.8424,c=95.8191u1,2=2(−99.8816)−(−1.8424)±(−1.8424)2−4(−99.8816)⋅95.8191
u1,2=2(−99.8816)−(−1.8424)±(−1.8424)2−4(−99.8816)⋅95.8191
(−1.8424)2−4(−99.8816)⋅95.8191=38285.654512
(−1.8424)2−4(−99.8816)⋅95.8191
規則を適用 −(−a)=a=(−1.8424)2+4⋅99.8816⋅95.8191
指数の規則を適用する: n が偶数であれば (−a)n=an(−1.8424)2=1.84242=1.84242+4⋅95.8191⋅99.8816
数を乗じる:4⋅99.8816⋅95.8191=38282.26007…=1.84242+38282.26007…
1.84242=3.39443776=3.39443776+38282.26007…
数を足す:3.39443776+38282.26007…=38285.654512=38285.654512
u1,2=2(−99.8816)−(−1.8424)±38285.654512
解を分離するu1=2(−99.8816)−(−1.8424)+38285.654512,u2=2(−99.8816)−(−1.8424)−38285.654512
u=2(−99.8816)−(−1.8424)+38285.654512:−199.76321.8424+38285.654512
2(−99.8816)−(−1.8424)+38285.654512
括弧を削除する: (−a)=−a,−(−a)=a=−2⋅99.88161.8424+38285.654512
数を乗じる:2⋅99.8816=199.7632=−199.76321.8424+38285.654512
分数の規則を適用する: −ba=−ba=−199.76321.8424+38285.654512
u=2(−99.8816)−(−1.8424)−38285.654512:199.763238285.654512−1.8424
2(−99.8816)−(−1.8424)−38285.654512
括弧を削除する: (−a)=−a,−(−a)=a=−2⋅99.88161.8424−38285.654512
数を乗じる:2⋅99.8816=199.7632=−199.76321.8424−38285.654512
分数の規則を適用する: −b−a=ba1.8424−38285.654512=−(38285.654512−1.8424)=199.763238285.654512−1.8424
二次equationの解:u=−199.76321.8424+38285.654512,u=199.763238285.654512−1.8424
代用を戻す u=cos(α)cos(α)=−199.76321.8424+38285.654512,cos(α)=199.763238285.654512−1.8424
cos(α)=−199.76321.8424+38285.654512,cos(α)=199.763238285.654512−1.8424
cos(α)=−199.76321.8424+38285.654512:α=arccos(−199.76321.8424+38285.654512)+2πn,α=−arccos(−199.76321.8424+38285.654512)+2πn
cos(α)=−199.76321.8424+38285.654512
三角関数の逆数プロパティを適用する
cos(α)=−199.76321.8424+38285.654512
以下の一般解 cos(α)=−199.76321.8424+38285.654512cos(x)=−a⇒x=arccos(−a)+2πn,x=−arccos(−a)+2πnα=arccos(−199.76321.8424+38285.654512)+2πn,α=−arccos(−199.76321.8424+38285.654512)+2πn
α=arccos(−199.76321.8424+38285.654512)+2πn,α=−arccos(−199.76321.8424+38285.654512)+2πn
cos(α)=199.763238285.654512−1.8424:α=arccos(199.763238285.654512−1.8424)+2πn,α=2π−arccos(199.763238285.654512−1.8424)+2πn
cos(α)=199.763238285.654512−1.8424
三角関数の逆数プロパティを適用する
cos(α)=199.763238285.654512−1.8424
以下の一般解 cos(α)=199.763238285.654512−1.8424cos(x)=a⇒x=arccos(a)+2πn,x=2π−arccos(a)+2πnα=arccos(199.763238285.654512−1.8424)+2πn,α=2π−arccos(199.763238285.654512−1.8424)+2πn
α=arccos(199.763238285.654512−1.8424)+2πn,α=2π−arccos(199.763238285.654512−1.8424)+2πn
すべての解を組み合わせるα=arccos(−199.76321.8424+38285.654512)+2πn,α=−arccos(−199.76321.8424+38285.654512)+2πn,α=arccos(199.763238285.654512−1.8424)+2πn,α=2π−arccos(199.763238285.654512−1.8424)+2πn
元のequationに当てはめて解を検算する
9.8sin(α)−0.29.8cos(α)=0.47 に当てはめて解を確認する
equationに一致しないものを削除する。
解答を確認する arccos(−199.76321.8424+38285.654512)+2πn:偽
arccos(−199.76321.8424+38285.654512)+2πn
挿入 n=1arccos(−199.76321.8424+38285.654512)+2π1
9.8sin(α)−0.29.8cos(α)=0.47の挿入向けα=arccos(−199.76321.8424+38285.654512)+2π19.8sin(arccos(−199.76321.8424+38285.654512)+2π1)−0.2⋅9.8cos(arccos(−199.76321.8424+38285.654512)+2π1)=0.47
改良3.40577…=0.47
⇒偽
解答を確認する −arccos(−199.76321.8424+38285.654512)+2πn:真
−arccos(−199.76321.8424+38285.654512)+2πn
挿入 n=1−arccos(−199.76321.8424+38285.654512)+2π1
9.8sin(α)−0.29.8cos(α)=0.47の挿入向けα=−arccos(−199.76321.8424+38285.654512)+2π19.8sin(−arccos(−199.76321.8424+38285.654512)+2π1)−0.2⋅9.8cos(−arccos(−199.76321.8424+38285.654512)+2π1)=0.47
改良0.47=0.47
⇒真
解答を確認する arccos(199.763238285.654512−1.8424)+2πn:真
arccos(199.763238285.654512−1.8424)+2πn
挿入 n=1arccos(199.763238285.654512−1.8424)+2π1
9.8sin(α)−0.29.8cos(α)=0.47の挿入向けα=arccos(199.763238285.654512−1.8424)+2π19.8sin(arccos(199.763238285.654512−1.8424)+2π1)−0.2⋅9.8cos(arccos(199.763238285.654512−1.8424)+2π1)=0.47
改良0.47=0.47
⇒真
解答を確認する 2π−arccos(199.763238285.654512−1.8424)+2πn:偽
2π−arccos(199.763238285.654512−1.8424)+2πn
挿入 n=12π−arccos(199.763238285.654512−1.8424)+2π1
9.8sin(α)−0.29.8cos(α)=0.47の挿入向けα=2π−arccos(199.763238285.654512−1.8424)+2π19.8sin(2π−arccos(199.763238285.654512−1.8424)+2π1)−0.2⋅9.8cos(2π−arccos(199.763238285.654512−1.8424)+2π1)=0.47
改良−4.27346…=0.47
⇒偽
α=−arccos(−199.76321.8424+38285.654512)+2πn,α=arccos(199.763238285.654512−1.8424)+2πn
10進法形式で解を証明するα=−2.99124…+2πn,α=0.24444…+2πn