1)sin(arctg 2 +arctg3) 2)tg(arcsin1/3+arccos1/4)

Лебедев Дмитрий Сергеевич

Учитель математики

Проверено учителем

Для решения подобных задач используются тригонометрические формулы сложения углов и взаимосвязь между обратными тригонометрическими функциями. 1) Вычисление sin(arctan2+arctan3)sine open paren arc tangent 2 plus arc tangent 3 close paren Пусть α=arctan2alpha equals arc tangent 2 и β=arctan3beta equals arc tangent 3. Тогда tanα=2tangent alpha equals 2 и tanβ=3tangent beta equals 3. Нам необходимо найти sin(α+β)sine open paren alpha plus beta close paren. Шаг 1: Формула сложения sin(α+β)=sinαcosβ+cosαsinβsine open paren alpha plus beta close paren equals sine alpha cosine beta plus cosine alpha sine betaШаг 2: Нахождение синусов и косинусов через тангенс Так как αalpha и βbeta — это углы, тангенсы которых положительны, они лежат в первой четверти ( 0<α,β<π/20 is less than alpha comma beta is less than pi / 2). Используем формулы: cosx=11+tan2x,sinx=tanx1+tan2xcosine x equals the fraction with numerator 1 and denominator the square root of 1 plus tangent squared x end-root end-fraction comma space sine x equals the fraction with numerator tangent x and denominator the square root of 1 plus tangent squared x end-root end-fraction

  • Для αalpha:
    cosα=11+22=15cosine alpha equals the fraction with numerator 1 and denominator the square root of 1 plus 2 squared end-root end-fraction equals the fraction with numerator 1 and denominator the square root of 5 end-root end-fraction
    sinα=21+22=25sine alpha equals the fraction with numerator 2 and denominator the square root of 1 plus 2 squared end-root end-fraction equals the fraction with numerator 2 and denominator the square root of 5 end-root end-fraction Для βbeta:
    cosβ=11+32=110cosine beta equals the fraction with numerator 1 and denominator the square root of 1 plus 3 squared end-root end-fraction equals the fraction with numerator 1 and denominator the square root of 10 end-root end-fraction
    sinβ=31+32=310sine beta equals the fraction with numerator 3 and denominator the square root of 1 plus 3 squared end-root end-fraction equals the fraction with numerator 3 and denominator the square root of 10 end-root end-fraction

Шаг 3: Подстановка в формулу sin(α+β)=25110+15310=2+350=552=12=22sine open paren alpha plus beta close paren equals the fraction with numerator 2 and denominator the square root of 5 end-root end-fraction center dot the fraction with numerator 1 and denominator the square root of 10 end-root end-fraction plus the fraction with numerator 1 and denominator the square root of 5 end-root end-fraction center dot the fraction with numerator 3 and denominator the square root of 10 end-root end-fraction equals the fraction with numerator 2 plus 3 and denominator the square root of 50 end-root end-fraction equals the fraction with numerator 5 and denominator 5 the square root of 2 end-root end-fraction equals the fraction with numerator 1 and denominator the square root of 2 end-root end-fraction equals the fraction with numerator the square root of 2 end-root and denominator 2 end-fraction Ответ: 22the fraction with numerator the square root of 2 end-root and denominator 2 end-fraction 2) Вычисление tan(arcsin13+arccos14)tangent open paren arc sine one-third plus arc cosine one-fourth close paren Пусть α=arcsin13alpha equals arc sine one-third и β=arccos14beta equals arc cosine one-fourth . Тогда sinα=13sine alpha equals one-third и cosβ=14cosine beta equals one-fourth . Нам нужно найти tan(α+β)tangent open paren alpha plus beta close paren. Шаг 1: Формула тангенса суммы tan(α+β)=tanα+tanβ1tanαtanβtangent open paren alpha plus beta close paren equals the fraction with numerator tangent alpha plus tangent beta and denominator 1 minus tangent alpha tangent beta end-fraction Шаг 2: Нахождение тангенсов Оба угла αalpha и βbeta лежат в первой четверти, так как их аргументы положительны.

  • Находим tanαtangent alpha:
    cosα=1sin2α=1(13)2=89=223cosine alpha equals the square root of 1 minus sine squared alpha end-root equals the square root of 1 minus open paren one-third close paren squared end-root equals the square root of eight-nineths end-root equals the fraction with numerator 2 the square root of 2 end-root and denominator 3 end-fraction
    tanα=sinαcosα=1/322/3=122=24tangent alpha equals the fraction with numerator sine alpha and denominator cosine alpha end-fraction equals the fraction with numerator 1 / 3 and denominator 2 the square root of 2 end-root / 3 end-fraction equals the fraction with numerator 1 and denominator 2 the square root of 2 end-root end-fraction equals the fraction with numerator the square root of 2 end-root and denominator 4 end-fraction Находим tanβtangent beta:
    sinβ=1cos2β=1(14)2=1516=154sine beta equals the square root of 1 minus cosine squared beta end-root equals the square root of 1 minus open paren one-fourth close paren squared end-root equals the square root of 15 over 16 end-fraction end-root equals the fraction with numerator the square root of 15 end-root and denominator 4 end-fraction
    tanβ=sinβcosβ=15/41/4=15tangent beta equals the fraction with numerator sine beta and denominator cosine beta end-fraction equals the fraction with numerator the square root of 15 end-root / 4 and denominator 1 / 4 end-fraction equals the square root of 15 end-root

Шаг 3: Подстановка в формулу tan(α+β)=24+1512415=2+41544304=2+415430tangent open paren alpha plus beta close paren equals the fraction with numerator the fraction with numerator the square root of 2 end-root and denominator 4 end-fraction plus the square root of 15 end-root and denominator 1 minus the fraction with numerator the square root of 2 end-root and denominator 4 end-fraction center dot the square root of 15 end-root end-fraction equals the fraction with numerator the fraction with numerator the square root of 2 end-root plus 4 the square root of 15 end-root and denominator 4 end-fraction and denominator the fraction with numerator 4 minus the square root of 30 end-root and denominator 4 end-fraction end-fraction equals the fraction with numerator the square root of 2 end-root plus 4 the square root of 15 end-root and denominator 4 minus the square root of 30 end-root end-fraction Для избавления от иррациональности в знаменателе (опционально) можно умножить на сопряженное, но в тригонометрии такой вид часто является конечным. Ответ: 2+415430the fraction with numerator the square root of 2 end-root plus 4 the square root of 15 end-root and denominator 4 minus the square root of 30 end-root end-fraction Могу помочь с вычислением производных этих функций или решением аналогичных тригонометрических уравнений.

Форма ответа

Ваш аватар