1-ctg2a=(1+ctg2a)(sin2a-cos2a)
1-ctg2a=(1+ctg2a)(sin2a-cos2a)
Ответ на вопрос
Let's simplify the given expression step by step:First, expand the right side of the equation:
(1 + ctg2a)(sin2a - cos2a) = sin2a + sin2a · ctg2a - cos2a - cos2a · ctg2a
= sin2a + tan2a · sin2a - cos2a - cos2a · tan2aNext, simplify the expression by using trigonometric identities:
tan2a = sin2a/cos2a
Therefore, tan2a · sin2a = sin2a/cos2a · sin2a = sin3a/cos2aApplying this simplification:
= sin2a + sin3a/cos2a - cos2a - cos3a/cos2a
= sin2a + sin3a/cos2a - cos2a - sin2a
= sin2a - cos2aNow, the left side of the equation:
1 - ctg2aSince cotangent is the reciprocal of tangent, and tan2a = sin2a/cos2a, then cot2a = cos2a/sin2a. Therefore, ctg2a = cos2a/sin2aNow, simplify the left side:
1 - ctg2a = 1 - cos2a/sin2a = (sin2a - cos2a)/sin2aSince (sin2a - cos2a)/sin2a = sin2a - cos2a, the left side simplifies to:
1 - ctg2a = sin2a - cos2aTherefore, the given equation simplifies to:
sin2a - cos2a = sin2a - cos2aThis confirms that the given expression is true.
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1-ctg2a=(1+ctg2a)(sin2a-cos2a) Проверить справедливость тождества
1-ctg2a=(1+ctg2a)(sin2a-cos2a) Проверить справедливость тождества
Ответ на вопрос
Для начала, разложим правую часть уравнения:(1+ctg2a)(sin2a-cos2a) = sin2a - cos2a + ctg2a(sin2a - cos2a)
= sin2a - cos2a + (cos2a/sin2a)(sin2a - cos2a)
= sin2a - cos2a + cos2a - cos^2(2a)/sin(2a)
= sin2a - cos^2(2a)/sin2a
= sin2a - (1-sin^2(2a))/sin2a
= sin2a - 1/sin2a + sin^3(2a)/sin2a
= sin2a - csc2a + sin^3(2a)/sin2a.Теперь подставим полученное в левую часть уравнения:1 - ctg2a = 1 - cos2a/sin2a
= (sin2a - cos2a) / sin2a
= sin2a - cos2a sin2a
= sin2a - cos2a.Таким образом, мы видим, что левая и правая части уравнения не равны, а значит, тождество не выполняется.
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A) Sin 2a cos 2a ctg2a -1;
B) tga/cigarette + 1;
A) Sin 2a cos 2a ctg2a -1; B) tga/cigarette + 1;
Ответ на вопрос
A) Simplifying the given expression:
sin(2a) cos(2a) ctg(2a) - 1
2sin(a)cos(a) 1/sin(2a) - 1
2sin(a)cos(a) 1/(2sin(a)cos(a)) - 1
1 - 1
0Therefore, the simplified expression is 0.B) tga/cigarette + 1 is not a valid mathematical expression as "cigarette" is not a recognized mathematical operation. Please provide a correct expression for further evaluation.
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Упростите выражение: а) (sina/ 1+cosa+sina/1-cosa)×1/1+ctg2a б) (1+cos2a)tg(2п-a)
Упростите выражение: а) (sina/ 1+cosa+sina/1-cosa)×1/1+ctg2a б) (1+cos2a)tg(2п-a)
Ответ на вопрос
а) (sina/ 1+cosa+sina/1-cosa)×1/1+ctg2a = sina/(1+cosa) + sina/(1-cosa) × 1 + ctg2a
= (sina(1-cosa) + sina(1+cosa))/(1-cosa^2) + 1 - tg2a
= (sina - (sina)(cosa) + sina + (sina)(cosa))/(sina^2) + 1 - tg2a
= (2sina)/(1-sina^2) + 1 - tg2aб) (1+cos2a)tg(2п-a) = (1 + cos2a)tg(pi - a)
= (1 + cos(2a))tg(pi - a)
= (1 + cos(a - a))tg(pi - a)
= (1 + (cosa)(cosa) - (sina)(sina))/(sina/cosa)
= (1 + cosa^2 - sina^2)/(sina/cosa)
= (1 + cosa^2 - (1 - cosa^2))/(sina/cosa)
= (2cosa^2)/(sina/cosa)
= 2cosa/sina
= 2cot(a)
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(ctg2a - cos2a)(1/cos2a - 1)
(ctg2a - cos2a)(1/cos2a - 1)
Ответ на вопрос
Let's start by simplifying the expression:(ctg^2a - cos^2a)(1/cos^2a - 1)We can re-write cotangent as 1/tan:
(1/tan^2a - cos^2a)(1/cos^2a - 1)Using the identity tan^2a + 1 = sec^2a, we can rewrite 1/tan^2a as sec^2a:
(sec^2a - cos^2a)(1/cos^2a - 1)Now, we can expand the expression:
sec^2a/cos^2a - cos^2a/cos^2a - sec^2a + cos^2aSimplifying further:
sec^2a/cos^2a - 1 - sec^2a + cos^2aNow we can substitute sec^2a for 1 + tan^2a:
(1 + tan^2a) / cos^2a - 1 - (1 + tan^2a) + cos^2aExpanding again:
tan^2a / cos^2a + 1 / cos^2a - 1 - 1 - tan^2a + cos^2aSimplifying:
tan^2a / cos^2a + 1 / cos^2a - 2 - tan^2a + cos^2aNow we can simplify further by using the trigonometric identities tan^2a = sec^2a - 1 and sec^2a = 1 + tan^2a:
(sec^2a - 1) / cos^2a + sec^2a / cos^2a - 2 - (sec^2a - 1) + cos^2aExpanding:
sec^2a / cos^2a - 1 / cos^2a + sec^2a / cos^2a - 2 - sec^2a + 1 + cos^2aSimplifying:
(sec^2a + sec^2a - 1) / cos^2a - 2 - sec^2a + cos^2aFurther simplification:
(2sec^2a - 1) / cos^2a - 2 - sec^2a + cos^2aAnd that is the simplified expression for (ctg^2a - cos^2a)(1/cos^2a - 1).
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1-ctg2a=(1+ctg2a)(son2a-cos2a)
1-ctg2a=(1+ctg2a)(son2a-cos2a)
Ответ на вопрос
To solve this equation, we will first expand both sides using the properties of trigonometric functions.Starting with the left side:
1 - ctg(2a)We know that cotangent is the reciprocal of tangent, so we can rewrite this as:1 - 1/tan(2a)We can take the reciprocal of tan(2a) by using the identity tan(x) = sin(x)/cos(x):1 - cos(2a)/sin(2a)Next, we will multiply both the numerator and denominator by sin(2a) to get a common denominator:sin(2a)/sin(2a) - cos(2a)/sin(2a)This simplifies to:sin(2a) - cos(2a)/sin(2a)Now moving on to the right side:
(1 + ctg(2a))(sin(2a) - cos(2a))Expanding this using the same steps as above, we get:(1 + 1/tan(2a))(sin(2a) - cos(2a))
(sin(2a) - cos(2a) + sin(2a) - cos(2a)/sin(2a))Simplifying this further:2sin(2a) - 2cos(2a)/sin(2a)Therefore, the equation simplifies to:sin(2a) - cos(2a)/sin(2a) = 2sin(2a) - 2cos(2a)/sin(2a)
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Упростите выражение cos2a+ctg2a-1/sin2a
Упростите выражение cos2a+ctg2a-1/sin2a
Ответ на вопрос
Для начала упростим выражение cos(2a) + ctg(2a) - 1/sin(2a) с использованием тригонометрических тождеств:cos(2a) = 1 - 2sin^2(a)
ctg(2a) = cot(2a) = cot(a)/2 - tan(a)/2
sin(2a) = 2sin(a)cos(a)Подставим полученные выражения обратно в исходное:1 - 2sin^2(a) + (cot(a)/2 - tan(a)/2) - 1/(2sin(a)cos(a))Упростим дальше:1 - 2sin^2(a) + cot(a)/2 - tan(a)/2 - 1/(2sin(a)cos(a))Поделим все слагаемые на 2:1/2 - sin^2(a) + cot(a)/4 - tan(a)/4 - 1/(4sin(a)cos(a))Теперь преобразуем:(1 - 2sin^2(a))/2 + cot(a)/4 - tan(a)/4 - 1/(4sin(a)cos(a))(1/2 - 1/2 * 2sin^2(a)) + cot(a)/4 - tan(a)/4 - csc(2a)/41/2 - sin^2(a) + cot(a)/4 - tan(a)/4 - csc(2a)/4Таким образом, упрощенное выражение равно:1/2 - sin^2(a) + cot(a)/4 - tan(a)/4 - csc(2a)/4
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а)1-sin2а/cos2а б)1-cos2a/1-sin2a в)(1+tg2a)-sin2a г)(ctg2a+1)*sin2a-cos2a
а)1-sin2а/cos2а б)1-cos2a/1-sin2a в)(1+tg2a)-sin2a г)(ctg2a+1)*sin2a-cos2a
Ответ на вопрос
а) (1 - sin^2(a))/cos^2(a) = cos^2(a)/cos^2(a) = 1
б) (1 - cos^2(a))/(1 - sin^2(a)) = sin^2(a)/cos^2(a) = tan^2(a)
в) (1 + tan^2(a)) - sin^2(a) = sec^2(a) - sin^2(a) = 1
г) (cot^2(a) + 1) * sin^2(a) - cos(a) = csc^2(a)sin^2(a) - cos(a) = 1 - cos(a)
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Докажите тождество: ctg2a*2tga/1+tg^2a=cos^2a.
Докажите тождество: ctg2a*2tga/1+tg^2a=cos^2a.
Ответ на вопрос
Исходное тождество:ctg(2a) * tg(a) / (1 + tg^2(a)) = cos^2(a)Для начала заменим ctg(2a) и tg(2a) через tg(a):ctg(2a) = 1 / tg(2a) = 1 / [2tg(a) / (1 - tg^2(a))] = (1 - tg^2(a)) / 2tg(a)Теперь заменим ctg(2a) и tg(a) в исходном тождестве:[(1 - tg^2(a)) / 2tg(a)] * tg(a) / [1 + tg^2(a)] = cos^2(a)[(1 - tg^2(a)) / 2] * [1 + tg(a)] = cos^2(a)(1 - tg^2(a)) / 2 = cos^2(a)cos^2(a) = cos^2(a)Тождество доказано.
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Если tg(A+П/4)=-1/3 то значение ctg2a =?
Если tg(A+П/4)=-1/3 то значение ctg2a =?
Ответ на вопрос
Для решения этого уравнения, сначала найдем значение тангенса угла A.tg(A+П/4) = -1/3tg(A) = tg(A+П/4 - П/4) = (tg(A+П/4) - tg(П/4))/(1 + tg(A+П/4)tg(П/4))tg(П/4) = 1tg(A) = (-1/3 - 1)/(1 + (-1/3)*1) = (-4/3)/(4/3) = -1Теперь найдем значение котангенса угла 2A, используя формулу:ctg(2A) = 1/tg(2A) = 1/(2tg(A)/(1-tg^2(A))) = 1/(2*(-1)/(1-(-1)^2)) = 1/(-2/(1-1)) = 0Итак, значение ctg(2A) равно 0.
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1/sin2a-1=ctg2a
1/sin2a-1=ctg2a
Ответ на вопрос
To prove the given equation, we can start by rewriting everything in terms of sines and cosines:1/sin(2a) - 1 = cot(2a)Since cot(2a) = cos(2a)/sin(2a), we can rewrite the equation as:1/sin(2a) - 1 = cos(2a)/sin(2a)Next, we can multiply both sides by sin(2a) to get rid of the fractions:1 - sin(2a) = cos(2a)Now, we can use the double angle identities to express sin(2a) and cos(2a) in terms of sin(a) and cos(a):sin(2a) = 2sin(a)cos(a)
cos(2a) = cos^2(a) - sin^2(a)Substitute these into the equation:1 - 2sin(a)cos(a) = cos^2(a) - sin^2(a)Now, we can use the Pythagorean identity sin^2(a) + cos^2(a) = 1 to simplify the equation:1 - 2sin(a)cos(a) = cos^2(a) - (1 - cos^2(a))1 - 2sin(a)cos(a) = cos^2(a) - 1 + cos^2(a)1 - 2sin(a)cos(a) = 2cos^2(a) - 1Rearranging terms gives:2sin(a)cos(a) + 2cos^2(a) = 2Now, divide everything by 2:sin(a)cos(a) + cos^2(a) = 1The left side of the equation is simply sin(a), which equals 1. Therefore, the original equation is proven to be true.
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