Қарапайым тригонометриялық теңдеулерді шешіңіз.
№ 1 Теңдеуді шешіңіз: ${\sin (0,5x) = – 1}$
Шешуі: $${0,5x = – \frac{\pi }{2} + 2\pi n;\quad n \in Z}$$ $${x = – \pi + 4\pi n;\quad n \in Z}$$ Жауабы: ${\left\{ { – \pi + 4\pi n} \right\}}$
№ 2 Аралықтағы ең үлкен шешімін табыңыз: ${\cos x = \frac{1}{2},\quad \left[ {700^\circ ;1050^\circ } \right]}$
Шешуі: $${x = \pm \arccos \frac{1}{2} + 2\pi n;\quad n \in Z}$$ $${x = \pm \frac{\pi }{3} + 2\pi n;\quad n \in Z}$$
$${40^\circ \le 60^\circ + 360^\circ n \le 1050^\circ }$$ $${640^\circ \le 360^\circ n \le 910^\circ }$$ $${1,7 \le n \le 2,52}$$ $${n = 2}$$
$${700^\circ \le – 60^\circ + 360^\circ n \le 1050^\circ }$$ $${760^\circ \le 360^\circ n \le 1110^\circ }$$ $${21 \le n \le 3,08}$$ $${n = 3.}$$
$${n = 2,}$$ $${\quad x = 60^\circ + 360^\circ \cdot 2 = 780^\circ }$$ $${n = 3,}$$ $${\quad x = – 60^\circ + 360^\circ \cdot 3 = 1020^\circ }$$ Жауабы: Ең үлкен шешімі: ${x = 1020^\circ }$
№ 3 Теңдеуді шешіңіз: ${\sin (\pi + x) + \cos \left( {\frac{\pi }{2} + x} \right) = – 1}$
Шешуі: $${ – \sin x – \sin x = – 1}$$ $${ – 2\sin x = – 1}$$ $${\sin x = \frac{1}{2}}$$ $${x = {{( – 1)}^k}\arcsin \frac{1}{2} + \pi k;\quad k \in Z}$$
Жауабы: ${x = {{( – 1)}^k}\frac{\pi }{6} + \pi k;\quad k \in Z}$
№ 4 Теңдеуді шешіңіз: ${2\sqrt 3 \tg ( – x) + 6 = 0}$
Шешуі: $${ – 2\sqrt 3 \tg x = – 6}$$ $${\tg x = \frac{{ – 6}}{{ – 2\sqrt 3 }}}$$ $${\tg x = \sqrt 3 }$$ $${x = \arctg \sqrt 3 + \pi n;\quad n \in Z}$$
Жауабы: ${x = \frac{\pi }{3} + \pi n;\quad n \in Z}$
№ 5 Теңдеуді шешіңіз: ${\cos \left( {x – \frac{\pi }{4}} \right) = – \frac{1}{2}}$
Шешуі: $${x – \frac{\pi }{4} = \pm \arccos \left( { – \frac{1}{2}} \right) + 2\pi n;}$$ $${\quad n \in Z}$$ $${x – \frac{\pi }{4} = \pm \frac{{2\pi }}{3} + 2\pi n;\quad n \in Z}$$ $${x = \pm \frac{{2\pi }}{3} + \frac{\pi }{4} + 2\pi n;\quad n \in Z}$$
Жауабы: ${ \pm \frac{{2\pi }}{3} + \frac{\pi }{4} + 2\pi n;\quad n \in Z}$
№ 6 Теңдеуді шешіңіз: ${\tg \left( {\frac{\pi }{4} – \frac{x}{2}} \right) = – 1}$
Шешуі: $${ – \tg \left( {\frac{x}{2} – \frac{\pi }{4}} \right) = – 1}$$ $${\tg \left( {\frac{x}{2} – \frac{\pi }{4}} \right) = 1}$$ $${\frac{x}{2} – \frac{\pi }{4} = \arctg 1 + \pi n;\quad n \in Z}$$ $${\frac{x}{2} – \frac{\pi }{4} = \frac{\pi }{4} + \pi n;\quad n \in Z}$$ $${\frac{x}{2} = \frac{\pi }{4} + \frac{\pi }{4} + \pi n;\quad n \in Z}$$ $${\frac{x}{2} = \frac{\pi }{2} + \pi n;\quad n \in Z}$$ $$x = \pi + 2\pi n;\quad n \in Z$$
Жауабы: $x = \pi \left( {1 + 2n} \right);\quad n \in Z$
№ 7 Теңдеуді шешіңіз: ${\cos \left( {\frac{{4x}}{3} + \frac{\pi }{3}} \right) = 1}$
Шешуі: $${\frac{{4x}}{3} + \frac{\pi }{3} = 2\pi n;\quad n \in Z}$$ $${\frac{{4x}}{3} = – \frac{\pi }{3} + 2\pi n;\quad n \in Z}$$ $${4x = – \pi + 6\pi n;\quad n \in Z}$$
Жауабы: ${x = – \frac{\pi }{4} + \frac{{3\pi n}}{2};\quad n \in Z}$
№ 8 Теңдеуді шешіңіз: ${\lg \cos x = 1}$
Шешуі: Анықталу облысы: $$\cos x \gt 0$$ $${\cos x = 10}$$ $${\cos x \in [ – 1;1]}$$
Жауабы: $\emptyset$
№ 9 Теңдеуді шешіңіз: ${\sin \left( {\frac{\pi }{4} – x} \right) = \frac{1}{2}}$
Шешуі: $$ – \sin \left( {x – \frac{\pi }{4}} \right) = \frac{1}{2}$$ $$\sin \left( {x – \frac{\pi }{4}} \right) = – \frac{1}{2}$$ $${x – \frac{\pi }{4} = {{( – 1)}^{n + 1}}\arcsin \frac{1}{2} + \pi n;}$$ $${\quad n \in Z}$$ $${x = {{( – 1)}^{n + 1}}\frac{\pi }{6} + \frac{\pi }{4} + \pi n;}$$ $${\quad n \in Z}$$
Жауабы: ${{{( – 1)}^{n + 1}}\frac{\pi }{6} + \frac{\pi }{4} + \pi n;\quad n \in Z}$
№ 10 Теңдеуді шешіңіз: $2\sin x\sin \left( {\frac{\pi }{2} – x} \right) = 1$
Шешуі: $$2\sin x\cos x = 1$$ $$\sin 2x = 1$$ $${2x = \frac{\pi }{2} + 2\pi n;\quad n \in Z}$$
Жауабы: ${x = \frac{\pi }{4} + \pi n;\quad n \in Z}$
№ 11 Теңдеуді шешіңіз: ${\frac{{\sqrt 3 }}{2}\tg \left( {2x – \frac{\pi }{4}} \right) = \sin \frac{\pi }{3}}$
Шешуі: $${\frac{{\sqrt 3 }}{2}\tg \left( {2x – \frac{\pi }{4}} \right) = \frac{{\sqrt 3 }}{2}}$$ $${\tg \left( {2x – \frac{\pi }{4}} \right) = 1}$$ $${2x – \frac{\pi }{4} = \arctg 1 + \pi n;\quad n \in Z}$$ $${2x – \frac{\pi }{4} = \frac{\pi }{4} + \pi n;\quad n \in Z}$$ $${2x = \frac{\pi }{2} + \pi n;\quad n \in Z}$$
Жауабы: ${x = \frac{\pi }{4} + \frac{{\pi n}}{2};\quad n \in Z}$
№ 12 Теңдеуді шешіңіз: ${\tg \left( {3x – 10^\circ } \right) = 0}$
Шешуі: $${3x – 10^\circ = \arctg 0 + \pi n;\quad n \in Z}$$ $${3x = 10^\circ + \pi n;\quad n \in Z}$$ $${x = \frac{{10^\circ }}{3} + \frac{{90^\circ n}}{3};\quad n \in Z}$$ $${x = \frac{{9^\circ 60′}}{3} + 30^\circ n;\quad n \in Z}$$
Жауабы: ${x = 3^\circ 20′ + 30^\circ n;\quad n \in Z}$
№ 13 Теңдеуді шешіңіз: ${\log _3}\cos x = 0$
Шешуі: Анықталу облысы: $$\cos x \gt 0$$ $$\cos x = {3^0}$$ $$\cos x = 1$$
Жауабы: $x = 2\pi n;\quad n \in Z$
№ 14 Теңдеуді шешіңіз: ${\left( {\cos \frac{x}{2} + 1} \right)\left( {{{\sin }^2}\frac{x}{2} + 2} \right) = 0}$
Шешуі:
$${\cos \frac{x}{2} + 1 = 0}$$ $${\cos \frac{x}{2} = – 1}$$ $${\frac{x}{2} = \pi + 2\pi n;\quad n \in Z}$$ $${x = 2\pi + 4\pi n;\quad n \in Z}$$
$${{{\sin }^2}\frac{x}{2} + 2 = 0}$$ $${{{\sin }^2}\frac{x}{2} = – 2}$$ $$\emptyset $$
Жауабы: $2\pi + 4\pi n;\quad n \in Z$
№ 15 Теңдеуді шешіңіз: ${\cos (x – 1) = \frac{{\sqrt 3 }}{2}}$
Шешуі: $${x – 1 = \pm \arccos \frac{{\sqrt 3 }}{2} + 2\pi n;}$$ $${\quad n \in Z}$$ $${x – 1 = \pm \frac{\pi }{6} + 2\pi n;\quad n \in Z}$$ $${x = \pm \frac{\pi }{6} + 1 + 2\pi n;\quad n \in Z}$$
Жауабы: $${1 \pm \frac{\pi }{6} + 2\pi n;\quad n \in Z}$$
№ 16 Теңдеуді шешіңіз: ${2\cos x + 3\sin x = 0}$
Шешуі: $${\frac{{2\cos x}}{{\cos x}} + \frac{{3\sin x}}{{\cos x}} = \frac{0}{{\cos x}}}$$ $${2 + 3\tg x = 0}$$ $${3\tg x = – 2}$$ $${\tg x = – \frac{2}{3}}$$ $${x = \arctg \left( { – \frac{2}{3}} \right) + \pi n;\quad n \in Z}$$ $${x = – \arctg \frac{2}{3} + \pi n;\quad n \in Z}$$
Жауабы: $${ -\arctg \frac{2}{3} + \pi n;\quad n \in Z}$$
№ 17 Теңдеуді шешіңіз: ${{3^{|\sin x – 1|}} = 9}$
Шешуі: $${{3^{|\sin x – 1|}} = {3^2}}$$ $${|\sin x – 1| = 2}$$
$${\sin x – 1 = 2}$$ $${\sin x = 3}$$ $${\sin x \in [ – 1;1]}$$ $$\emptyset$$
$${\sin x – 1 = – 2}$$ $${\sin x = – 1}$$ $${x = – \frac{\pi }{2} + 2\pi n;\quad n \in Z}$$
Жауабы: ${ – \frac{\pi }{2} + 2\pi n;\quad n \in Z}$
№ 18 Теңдеуді шешіңіз: ${{4^{\sin x\cos x}} = \sqrt 2 }$
Шешуі: $${{2^{2\sin x\cos x}} = {2^{\frac{1}{2}}}}$$ $${2\sin x\cos x = \frac{1}{2}}$$ $${\sin 2x = \frac{1}{2}}$$ $${2x = {{( – 1)}^n}\arcsin \frac{1}{2} + \pi n;\quad n \in Z}$$ $${2x = {{( – 1)}^n}\frac{\pi }{6} + \pi n,}$$ $${\quad n \in Z}$$ $${x = {{( – 1)}^n}\frac{\pi }{{12}} + \frac{{\pi n}}{2};\quad n \in Z}$$
Жауабы: ${{{( – 1)}^n}\frac{\pi }{{12}} + \frac{{\pi n}}{2};\quad n \in Z}$
№ 19 Теңдеуді шешіңіз: ${1 + 2\sin \frac{{\pi x}}{3} = 0}$
Шешуі: $${2\sin \frac{{\pi x}}{3} = – 1}$$ $${\sin \frac{{\pi x}}{3} = – \frac{1}{2}}$$ $${\frac{{\pi x}}{3} = {{( – 1)}^{n + 1}}\arcsin \frac{1}{2} + \pi n;}$$ $${\quad n \in Z}$$ $${\frac{{\pi x}}{3} = {{( – 1)}^{n + 1}}\frac{\pi }{6} + \pi n;\quad n \in Z}$$ $${\frac{x}{3} = {{( – 1)}^{n + 1}}\frac{1}{6} + n;\quad n \in Z}$$ $${x = {{( – 1)}^{n + 1}}\frac{1}{2} + 3n;\quad n \in Z}$$ $${2 \lt {{( – 1)}^{n + 1}}\frac{1}{2} + 3n \lt 4}$$
$${2 \lt – \frac{1}{2} + 3n \lt 4}$$ $${2,5 \lt 3n \lt 4,5}$$ $${0,83 \lt n \lt 1,5}$$ $${n = 1.}$$
$${2 \lt \frac{1}{2} + 3n \lt 4}$$ $${1,5 \lt 3n \lt 3,5}$$ $${0,5 \lt n \lt 1,16}$$ $${n = 1.}$$
$$x = {( – 1)^{1 + 1}}\frac{1}{2} + 3 \cdot 1 =$$ $$= \frac{1}{2} + 3 = 3,5$$ Жауабы: $\quad x = 3,5$
№ 20 Теңдеуді шешіңіз: ${5^{1 + {{\log }_5}\cos x}} = 2,5$
Шешуі: $${5^1} \cdot {5^{{{\log }_5}\cos x}} = 2,5$$ Анықталу облысы: ${\cos x \gt 0}$ $${5 \cdot \cos x = 2,5}$$ $${\cos x = \frac{1}{2}}$$ $${x = \pm \arccos \frac{1}{2} + 2\pi n;\quad n \in Z}$$
Жауабы: ${x = \pm \frac{\pi }{3} + 2\pi n;\quad n \in Z}$
№ 21 Теңдеуді шешіңіз: ${\sin (\pi \cos 3x) = 1}$
Шешуі:
$${\pi \cos 3x = \frac{\pi }{2} + 2\pi n;\quad n \in Z}$$ $${\cos 3x = \frac{1}{2} + 2n;\quad n \in Z}$$ $${\cos 3x \in [ – 1;1]}$$ $${ – 1 \le \frac{1}{2} + 2n \le 1}$$ $${ – 1,5 \le 2n \le 0,5}$$ $${ – 0,75 \le n \le 0,25,\quad n = 0}$$
$${\cos 3x = \frac{1}{2} + 2 \cdot 0}$$ $${\cos 3x = \frac{1}{2}}$$ $${3x = \pm \arccos \frac{1}{2} + 2\pi n;\quad n \in Z}$$ $${3x = \pm \frac{\pi }{3} + 2\pi n;\quad n \in Z}$$ $${x = \pm \frac{\pi }{9} + \frac{{2\pi n}}{3};\quad n \in Z}$$
Жауабы: ${ \pm \frac{\pi }{9} + \frac{{2\pi n}}{3};\quad n \in Z}$
№ 22 Теңдеуді шешіңіз: $${{8^{{{\sin }^2}x}} – {2^{{{\cos }^2}x}} = 0}$$
Шешуі:
$${{2^{3{{\sin }^2}x}} = {2^{{{\cos }^2}x}}}$$ $${3{{\sin }^2}x = {{\cos }^2}x}$$ $${3{{\sin }^2}x – \left( {1 – {{\sin }^2}x} \right) = 0}$$ $${4{{\sin }^2}x – 1 = 0}$$ $${4 \cdot \frac{{1 – \cos 2x}}{2} – 1 = 0}$$ $${2(1 – \cos 2x) – 1 = 0}$$ $${2 – 2\cos 2x – 1 = 0}$$
$${2\cos 2x = 1}$$ $${\cos 2x = \frac{1}{2}}$$ $${2x = \pm \arccos \frac{1}{2} + 2\pi n;\quad n \in Z}$$ $${2x = \pm \frac{\pi }{3} + 2\pi n;\quad n \in Z}$$ $${x = \pm \frac{\pi }{6} + \pi n;\quad n \in Z}$$
Жауабы: ${ \pm \frac{\pi }{6} + \pi n;\quad n \in Z}$
№ 23 Ең кіші оң түбірін табыңыз: $(3\cos \pi x – \pi )(2\sin \pi x – \sqrt 3 ) = 0$
Шешуі:
$${3\cos \pi x – \pi = 0}$$ $${3\cos \pi x = \pi }$$ $${\cos \pi x = \frac{\pi }{3}}$$ $${\cos \pi x \in [ – 1;1]}$$ $$\emptyset $$
$${2\sin \pi x – \sqrt 3 = 0}$$ $${\sin \pi x = \frac{{\sqrt 3 }}{2}}$$ $${\pi x = {{( – 1)}^n}\arcsin \frac{{\sqrt 3 }}{2} + \pi n;}$$ $${\quad n \in Z}$$ $${\pi x = {{( – 1)}^n}\frac{\pi }{3} + \pi n;\quad n \in Z}$$
$$x = {( – 1)^n}\frac{1}{3} + n;\quad n \in Z$$
$$n – \text{тақ болса},\quad – \frac{1}{3} + n \gt 0$$ $${n \gt \frac{1}{3},\quad n = 1}$$ $${n = 1,\quad x = – \frac{1}{3} + 1 = \frac{2}{3}}$$
$$n – \text{жұп болса} ,\quad \frac{1}{3} + n \gt 0$$ $$n \gt – \frac{1}{3},\quad n = 0$$ $${n = 0,\quad x = \frac{1}{3} + 0 = \frac{1}{3}}$$
Жауабы: Ең кіші оң түбірі ${\frac{1}{3}}$
№ 24 Теңдеуді шешіңіз: ${\dfrac{{\cos x}}{{\sin x – 1}} = 0}$
Шешуі:
$${\cos x = 0}$$ $${x = \frac{\pi }{2} + \pi n;\quad n \in Z}$$
$${\sin x – 1 \ne 0.}$$ $${\sin x \ne 1}$$ $${x \ne \frac{\pi }{2} + 2\pi n;\quad n \in Z}$$
Жауабы: $x = – \frac{\pi }{2} + 2\pi n;\quad n \in Z$
№ 25 Теңдеуді шешіңіз: ${1 + 2\cos \frac{{\pi x}}{{15}} = 0}$
Шешуі:
$${2\cos \frac{{\pi x}}{{15}} = – 1}$$ $${\cos \frac{{\pi x}}{{15}} = – \frac{1}{2}}$$ $${\frac{{\pi x}}{{15}} = \pm \arccos \left( { – \frac{1}{2}} \right) + 2\pi n;}$$ $${\quad n \in Z}$$
$${\frac{{\pi x}}{{15}} = \pm \frac{{2\pi }}{3} + 2\pi n;\quad n \in Z}$$ $${\frac{x}{{15}} = \pm \frac{2}{3} + 2n;\quad n \in Z}$$ $${x = \pm 10 + 30n;\quad n \in Z}$$
Жауабы: ${x = \pm 10 + 30n;\quad n \in Z}$
№ 26 Теңдеуді шешіңіз: $\dfrac{{\cos x – \frac{1}{2}}}{{\sin x – \frac{{\sqrt 3 }}{2}}} = 0.$
Шешуі:
$${\cos x – \frac{1}{2} = 0}$$ $${\cos x = \frac{1}{2}}$$ $${x = \pm \frac{\pi }{3} + 2\pi n,\quad n \in Z}$$
$${\sin x – \frac{{\sqrt 3 }}{2} \ne 0}$$ $${\sin x \ne \frac{{\sqrt 3 }}{2}}$$ $${x \ne {{( – 1)}^n}\arcsin \frac{{\sqrt 3 }}{2} + \pi n;}$$ $${\quad n \in Z}$$ $$x \ne {( – 1)^n}\frac{\pi }{3} + \pi n;\quad n \in Z$$
Жауабы: $x = – \frac{\pi }{3} + 2\pi n;\quad n \in Z$
№ 27 Теңдеуді шешіңіз: $|\sin 2x| = 1$
Шешуі:
$${\sin 2x = 1}$$ $${2x = \frac{\pi }{2} + 2\pi n;\quad n \in Z}$$ $${x = \frac{\pi }{4} + \pi n;\quad n \in Z}$$ $$x = \frac{\pi }{4} + \frac{{\pi n}}{2},\quad n \in Z$$
$${\sin 2x = – 1}$$ $${2x = – \frac{\pi }{2} + 2\pi n;\quad n \in Z}$$ $${x = – \frac{\pi }{4} + \pi n;\quad n \in Z}$$
Жауабы: $x = \frac{\pi }{4} + \frac{{\pi n}}{2},\quad n \in Z$
№ 28 Теңдеуді шешіңіз: $\dfrac{{\tg 3x}}{{\sin x}} = 0.$
Шешуі:
$$\tg 3x = 0$$ $$3x = \arctg 0 + \pi n;\quad n \in Z$$ $$x = \frac{{\pi n}}{3}\quad n \in Z$$
$$\sin x \ne 0$$ $$x \ne \pi n;\quad n \in Z$$
Жауабы: $$x = \pm \frac{\pi }{3} + \pi n;\quad n \in Z$$
№ 29 Теңдеуді шешіңіз: ${{{\cos }^2}2x = \frac{1}{2}}$
Шешуі:
$${\frac{{1 + \cos 4x}}{2} = \frac{1}{2}}$$ $${1 + \cos 4x = 1}$$ $${\cos 4x = 0}$$
$${4x = \frac{\pi }{2} + \pi n;\quad n \in Z}$$ $${x = \frac{\pi }{8} + \frac{{\pi n}}{4};\quad n \in Z}$$
Жауабы: ${\frac{\pi }{8} + \frac{{\pi n}}{4};\quad n \in Z}$
№ 30 Теңдеуді шешіңіз: ${{{\sin }^2}2x = \frac{1}{2}}$
Шешуі:
$${\frac{{1 – \cos 4x}}{2} = \frac{1}{2}}$$ $${1 – \cos 4x = 1}$$ $${\cos 4x = 0}$$
$${4x = \frac{\pi }{2} + \pi n;\quad n \in Z}$$ $${x = \frac{\pi }{8} + \frac{{\pi n}}{4};\quad n \in Z}$$
Жауабы: ${\frac{\pi }{8} + \frac{{\pi n}}{4};\quad n \in Z}$
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