해법
4sin(2x−0.4)−5cos(2x−0.4)=0
해법
x=21.29605…+2πn
+1
도
x=37.12925…∘+90∘n솔루션 단계
4sin(2x−0.4)−5cos(2x−0.4)=0
삼각성을 사용하여 다시 쓰기
4sin(2x−0.4)−5cos(2x−0.4)=0
삼각성을 사용하여 다시 쓰기
sin(2x−0.4)
각도 차이 식별 사용: sin(s−t)=sin(s)cos(t)−cos(s)sin(t)=sin(2x)cos(0.4)−cos(2x)sin(0.4)
sin(2x)cos(0.4)−cos(2x)sin(0.4)단순화하세요:0.92106…sin(2x)−0.38941…cos(2x)
sin(2x)cos(0.4)−cos(2x)sin(0.4)
cos(0.4)단순화하세요:0.92106…
cos(0.4)
cos(0.4)=0.92106…=0.92106…
=0.92106…sin(2x)−sin(0.4)cos(2x)
sin(0.4)단순화하세요:0.38941…
sin(0.4)
sin(0.4)=0.38941…=0.38941…
=0.92106…sin(2x)−0.38941…cos(2x)
=0.92106…sin(2x)−0.38941…cos(2x)
각도 차이 식별 사용: cos(s−t)=cos(s)cos(t)+sin(s)sin(t)=cos(2x)cos(0.4)+sin(2x)sin(0.4)
cos(2x)cos(0.4)+sin(2x)sin(0.4)단순화하세요:0.92106…cos(2x)+0.38941…sin(2x)
cos(2x)cos(0.4)+sin(2x)sin(0.4)
cos(0.4)단순화하세요:0.92106…
cos(0.4)
cos(0.4)=0.92106…=0.92106…
=0.92106…cos(2x)+sin(0.4)sin(2x)
sin(0.4)단순화하세요:0.38941…
sin(0.4)
sin(0.4)=0.38941…=0.38941…
=0.92106…cos(2x)+0.38941…sin(2x)
=0.92106…cos(2x)+0.38941…sin(2x)
4(0.92106…sin(2x)−0.38941…cos(2x))−5(0.92106…cos(2x)+0.38941…sin(2x))=0
4(0.92106…sin(2x)−0.38941…cos(2x))−5(0.92106…cos(2x)+0.38941…sin(2x))단순화하세요:1.73715…sin(2x)−6.16297…cos(2x)
4(0.92106…sin(2x)−0.38941…cos(2x))−5(0.92106…cos(2x)+0.38941…sin(2x))
4(0.92106…sin(2x)−0.38941…cos(2x))확대한다:3.68424…sin(2x)−1.55767…cos(2x)
4(0.92106…sin(2x)−0.38941…cos(2x))
분배 법칙 적용: a(b−c)=ab−aca=4,b=0.92106…sin(2x),c=0.38941…cos(2x)=4⋅0.92106…sin(2x)−4⋅0.38941…cos(2x)
4⋅0.92106…sin(2x)−4⋅0.38941…cos(2x)단순화하세요:3.68424…sin(2x)−1.55767…cos(2x)
4⋅0.92106…sin(2x)−4⋅0.38941…cos(2x)
숫자를 곱하시오: 4⋅0.92106…=3.68424…=3.68424…sin(2x)−4⋅0.38941…cos(2x)
숫자를 곱하시오: 4⋅0.38941…=1.55767…=3.68424…sin(2x)−1.55767…cos(2x)
=3.68424…sin(2x)−1.55767…cos(2x)
=3.68424…sin(2x)−1.55767…cos(2x)−5(0.92106…cos(2x)+0.38941…sin(2x))
−5(0.92106…cos(2x)+0.38941…sin(2x))확대한다:−4.60530…cos(2x)−1.94709…sin(2x)
−5(0.92106…cos(2x)+0.38941…sin(2x))
분배 법칙 적용: a(b+c)=ab+aca=−5,b=0.92106…cos(2x),c=0.38941…sin(2x)=−5⋅0.92106…cos(2x)+(−5)⋅0.38941…sin(2x)
마이너스 플러스 규칙 적용+(−a)=−a=−5⋅0.92106…cos(2x)−5⋅0.38941…sin(2x)
−5⋅0.92106…cos(2x)−5⋅0.38941…sin(2x)단순화하세요:−4.60530…cos(2x)−1.94709…sin(2x)
−5⋅0.92106…cos(2x)−5⋅0.38941…sin(2x)
숫자를 곱하시오: 5⋅0.92106…=4.60530…=−4.60530…cos(2x)−5⋅0.38941…sin(2x)
숫자를 곱하시오: 5⋅0.38941…=1.94709…=−4.60530…cos(2x)−1.94709…sin(2x)
=−4.60530…cos(2x)−1.94709…sin(2x)
=3.68424…sin(2x)−1.55767…cos(2x)−4.60530…cos(2x)−1.94709…sin(2x)
3.68424…sin(2x)−1.55767…cos(2x)−4.60530…cos(2x)−1.94709…sin(2x)단순화하세요:1.73715…sin(2x)−6.16297…cos(2x)
3.68424…sin(2x)−1.55767…cos(2x)−4.60530…cos(2x)−1.94709…sin(2x)
유사 요소 추가: −1.55767…cos(2x)−4.60530…cos(2x)=−6.16297…cos(2x)=3.68424…sin(2x)−6.16297…cos(2x)−1.94709…sin(2x)
유사 요소 추가: 3.68424…sin(2x)−1.94709…sin(2x)=1.73715…sin(2x)=1.73715…sin(2x)−6.16297…cos(2x)
=1.73715…sin(2x)−6.16297…cos(2x)
1.73715…sin(2x)−6.16297…cos(2x)=0
cos(2x),cos(2x)=0양쪽을 다음으로 나눕니다cos(2x)1.73715…sin(2x)−6.16297…cos(2x)=cos(2x)0
단순화cos(2x)1.73715…sin(2x)−6.16297…=0
기본 삼각형 항등식 사용: cos(x)sin(x)=tan(x)1.73715…tan(2x)−6.16297…=0
1.73715…tan(2x)−6.16297…=0
6.16297…를 오른쪽으로 이동
1.73715…tan(2x)−6.16297…=0
더하다 6.16297… 양쪽으로1.73715…tan(2x)−6.16297…+6.16297…=0+6.16297…
단순화1.73715…tan(2x)=6.16297…
1.73715…tan(2x)=6.16297…
양쪽을 다음으로 나눕니다 1.73715…
1.73715…tan(2x)=6.16297…
양쪽을 다음으로 나눕니다 1.73715…1.73715…1.73715…tan(2x)=1.73715…6.16297…
단순화tan(2x)=3.54774…
tan(2x)=3.54774…
트리거 역속성 적용
tan(2x)=3.54774…
일반 솔루션 tan(2x)=3.54774…tan(x)=a⇒x=arctan(a)+πn2x=arctan(3.54774…)+πn
2x=arctan(3.54774…)+πn
2x=arctan(3.54774…)+πn해결 :x=2arctan(3.54774…)+2πn
2x=arctan(3.54774…)+πn
양쪽을 다음으로 나눕니다 2
2x=arctan(3.54774…)+πn
양쪽을 다음으로 나눕니다 222x=2arctan(3.54774…)+2πn
단순화x=2arctan(3.54774…)+2πn
x=2arctan(3.54774…)+2πn
x=2arctan(3.54774…)+2πn
해를 10진수 형식으로 표시x=21.29605…+2πn