解
21.16=19.6sin(x)−29.4cos(x)
解
x=−2.80086…+2πn,x=1.62485…+2πn
+1
度
x=−160.47763…∘+360∘n,x=93.09749…∘+360∘n解答ステップ
21.16=19.6sin(x)−29.4cos(x)
両辺に29.4cos(x)を足す19.6sin(x)=21.16+29.4cos(x)
両辺を2乗する(19.6sin(x))2=(21.16+29.4cos(x))2
両辺から(21.16+29.4cos(x))2を引く384.16sin2(x)−447.7456−1244.208cos(x)−864.36cos2(x)=0
三角関数の公式を使用して書き換える
−447.7456−1244.208cos(x)+384.16sin2(x)−864.36cos2(x)
ピタゴラスの公式を使用する: cos2(x)+sin2(x)=1sin2(x)=1−cos2(x)=−447.7456−1244.208cos(x)+384.16(1−cos2(x))−864.36cos2(x)
簡素化 −447.7456−1244.208cos(x)+384.16(1−cos2(x))−864.36cos2(x):−1248.52cos2(x)−1244.208cos(x)−63.5856
−447.7456−1244.208cos(x)+384.16(1−cos2(x))−864.36cos2(x)
拡張 384.16(1−cos2(x)):384.16−384.16cos2(x)
384.16(1−cos2(x))
分配法則を適用する: a(b−c)=ab−aca=384.16,b=1,c=cos2(x)=384.16⋅1−384.16cos2(x)
=1⋅384.16−384.16cos2(x)
数を乗じる:1⋅384.16=384.16=384.16−384.16cos2(x)
=−447.7456−1244.208cos(x)+384.16−384.16cos2(x)−864.36cos2(x)
簡素化 −447.7456−1244.208cos(x)+384.16−384.16cos2(x)−864.36cos2(x):−1248.52cos2(x)−1244.208cos(x)−63.5856
−447.7456−1244.208cos(x)+384.16−384.16cos2(x)−864.36cos2(x)
類似した元を足す:−384.16cos2(x)−864.36cos2(x)=−1248.52cos2(x)=−447.7456−1244.208cos(x)+384.16−1248.52cos2(x)
条件のようなグループ=−1244.208cos(x)−1248.52cos2(x)−447.7456+384.16
数を足す/引く:−447.7456+384.16=−63.5856=−1248.52cos2(x)−1244.208cos(x)−63.5856
=−1248.52cos2(x)−1244.208cos(x)−63.5856
=−1248.52cos2(x)−1244.208cos(x)−63.5856
−63.5856−1244.208cos(x)−1248.52cos2(x)=0
置換で解く
−63.5856−1244.208cos(x)−1248.52cos2(x)=0
仮定:cos(x)=u−63.5856−1244.208u−1248.52u2=0
−63.5856−1244.208u−1248.52u2=0:u=−2497.041244.208+1230501.974016,u=−2497.041244.208−1230501.974016
−63.5856−1244.208u−1248.52u2=0
標準的な形式で書く ax2+bx+c=0−1248.52u2−1244.208u−63.5856=0
解くとthe二次式
−1248.52u2−1244.208u−63.5856=0
二次Equationの公式:
次の場合: a=−1248.52,b=−1244.208,c=−63.5856u1,2=2(−1248.52)−(−1244.208)±(−1244.208)2−4(−1248.52)(−63.5856)
u1,2=2(−1248.52)−(−1244.208)±(−1244.208)2−4(−1248.52)(−63.5856)
(−1244.208)2−4(−1248.52)(−63.5856)=1230501.974016
(−1244.208)2−4(−1248.52)(−63.5856)
規則を適用 −(−a)=a=(−1244.208)2−4⋅1248.52⋅63.5856
指数の規則を適用する: n が偶数であれば (−a)n=an(−1244.208)2=1244.2082=1244.2082−4⋅63.5856⋅1248.52
数を乗じる:4⋅1248.52⋅63.5856=317551.573248=1244.2082−317551.573248
1244.2082=1548053.547264=1548053.547264−317551.573248
数を引く:1548053.547264−317551.573248=1230501.974016=1230501.974016
u1,2=2(−1248.52)−(−1244.208)±1230501.974016
解を分離するu1=2(−1248.52)−(−1244.208)+1230501.974016,u2=2(−1248.52)−(−1244.208)−1230501.974016
u=2(−1248.52)−(−1244.208)+1230501.974016:−2497.041244.208+1230501.974016
2(−1248.52)−(−1244.208)+1230501.974016
括弧を削除する: (−a)=−a,−(−a)=a=−2⋅1248.521244.208+1230501.974016
数を乗じる:2⋅1248.52=2497.04=−2497.041244.208+1230501.974016
分数の規則を適用する: −ba=−ba=−2497.041244.208+1230501.974016
u=2(−1248.52)−(−1244.208)−1230501.974016:−2497.041244.208−1230501.974016
2(−1248.52)−(−1244.208)−1230501.974016
括弧を削除する: (−a)=−a,−(−a)=a=−2⋅1248.521244.208−1230501.974016
数を乗じる:2⋅1248.52=2497.04=−2497.041244.208−1230501.974016
分数の規則を適用する: −ba=−ba=−2497.041244.208−1230501.974016
二次equationの解:u=−2497.041244.208+1230501.974016,u=−2497.041244.208−1230501.974016
代用を戻す u=cos(x)cos(x)=−2497.041244.208+1230501.974016,cos(x)=−2497.041244.208−1230501.974016
cos(x)=−2497.041244.208+1230501.974016,cos(x)=−2497.041244.208−1230501.974016
cos(x)=−2497.041244.208+1230501.974016:x=arccos(−2497.041244.208+1230501.974016)+2πn,x=−arccos(−2497.041244.208+1230501.974016)+2πn
cos(x)=−2497.041244.208+1230501.974016
三角関数の逆数プロパティを適用する
cos(x)=−2497.041244.208+1230501.974016
以下の一般解 cos(x)=−2497.041244.208+1230501.974016cos(x)=−a⇒x=arccos(−a)+2πn,x=−arccos(−a)+2πnx=arccos(−2497.041244.208+1230501.974016)+2πn,x=−arccos(−2497.041244.208+1230501.974016)+2πn
x=arccos(−2497.041244.208+1230501.974016)+2πn,x=−arccos(−2497.041244.208+1230501.974016)+2πn
cos(x)=−2497.041244.208−1230501.974016:x=arccos(−2497.041244.208−1230501.974016)+2πn,x=−arccos(−2497.041244.208−1230501.974016)+2πn
cos(x)=−2497.041244.208−1230501.974016
三角関数の逆数プロパティを適用する
cos(x)=−2497.041244.208−1230501.974016
以下の一般解 cos(x)=−2497.041244.208−1230501.974016cos(x)=−a⇒x=arccos(−a)+2πn,x=−arccos(−a)+2πnx=arccos(−2497.041244.208−1230501.974016)+2πn,x=−arccos(−2497.041244.208−1230501.974016)+2πn
x=arccos(−2497.041244.208−1230501.974016)+2πn,x=−arccos(−2497.041244.208−1230501.974016)+2πn
すべての解を組み合わせるx=arccos(−2497.041244.208+1230501.974016)+2πn,x=−arccos(−2497.041244.208+1230501.974016)+2πn,x=arccos(−2497.041244.208−1230501.974016)+2πn,x=−arccos(−2497.041244.208−1230501.974016)+2πn
元のequationに当てはめて解を検算する
19.6sin(x)−29.4cos(x)=21.16 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(−2497.041244.208+1230501.974016)+2πn:偽
arccos(−2497.041244.208+1230501.974016)+2πn
挿入 n=1arccos(−2497.041244.208+1230501.974016)+2π1
19.6sin(x)−29.4cos(x)=21.16の挿入向けx=arccos(−2497.041244.208+1230501.974016)+2π119.6sin(arccos(−2497.041244.208+1230501.974016)+2π1)−29.4cos(arccos(−2497.041244.208+1230501.974016)+2π1)=21.16
改良34.25965…=21.16
⇒偽
解答を確認する −arccos(−2497.041244.208+1230501.974016)+2πn:真
−arccos(−2497.041244.208+1230501.974016)+2πn
挿入 n=1−arccos(−2497.041244.208+1230501.974016)+2π1
19.6sin(x)−29.4cos(x)=21.16の挿入向けx=−arccos(−2497.041244.208+1230501.974016)+2π119.6sin(−arccos(−2497.041244.208+1230501.974016)+2π1)−29.4cos(−arccos(−2497.041244.208+1230501.974016)+2π1)=21.16
改良21.16=21.16
⇒真
解答を確認する arccos(−2497.041244.208−1230501.974016)+2πn:真
arccos(−2497.041244.208−1230501.974016)+2πn
挿入 n=1arccos(−2497.041244.208−1230501.974016)+2π1
19.6sin(x)−29.4cos(x)=21.16の挿入向けx=arccos(−2497.041244.208−1230501.974016)+2π119.6sin(arccos(−2497.041244.208−1230501.974016)+2π1)−29.4cos(arccos(−2497.041244.208−1230501.974016)+2π1)=21.16
改良21.16=21.16
⇒真
解答を確認する −arccos(−2497.041244.208−1230501.974016)+2πn:偽
−arccos(−2497.041244.208−1230501.974016)+2πn
挿入 n=1−arccos(−2497.041244.208−1230501.974016)+2π1
19.6sin(x)−29.4cos(x)=21.16の挿入向けx=−arccos(−2497.041244.208−1230501.974016)+2π119.6sin(−arccos(−2497.041244.208−1230501.974016)+2π1)−29.4cos(−arccos(−2497.041244.208−1230501.974016)+2π1)=21.16
改良−17.98273…=21.16
⇒偽
x=−arccos(−2497.041244.208+1230501.974016)+2πn,x=arccos(−2497.041244.208−1230501.974016)+2πn
10進法形式で解を証明するx=−2.80086…+2πn,x=1.62485…+2πn