100Б.Помогите решить задачу!Преобразуйте в сумму тригонометрических функций прои...

aslanrozuev2020 @aslanrozuev2020

October 2021 1 17 Report

100Б.Помогите решить задачу!
Преобразуйте в сумму тригонометрических функций произведенние: 2sin10° * cos15° * cos25°

Answers & Comments

Artem112

Verified answer

$2\sin10^\circ\cdot\cos15^\circ\cdot\cos25^\circ=2\cdot(\sin10^\circ\cdot\cos15^\circ)\cdot\cos25^\circ=$

$=2\cdot\dfrac{1}{2} (\sin(10^\circ+15^\circ)+\sin(10^\circ-15^\circ))\cdot\cos25^\circ=$

$=(\sin25^\circ+\sin(-5^\circ))\cdot\cos25^\circ=(\sin25^\circ-\sin5^\circ)\cdot\cos25^\circ=$

$=\sin25^\circ\cdot\cos25^\circ-\sin5^\circ\cdot\cos25^\circ=$

$=\dfrac{1}{2}( \sin(25^\circ+25^\circ)+\sin(25^\circ-25^\circ))-\dfrac{1}{2}( \sin(5^\circ+25^\circ)+\sin(5^\circ-25^\circ))=$

$=\dfrac{1}{2}( \sin50^\circ+\sin0^\circ)-\dfrac{1}{2}( \sin30^\circ+\sin(-20^\circ))=$

$=\dfrac{1}{2}( \sin50^\circ+0)-\dfrac{1}{2}\left( \dfrac{1}{2} -\sin20^\circ\right)=\dfrac{1}{2} \sin50^\circ+\dfrac{1}{2}\sin20^\circ\right-\dfrac{1}{4}$

2 votes Thanks 1

Answers & Comments

Verified answer

pomogite resheniem dayu 50 ballovv ponedelnik konditer izgotavlivaet 102 pirozhnyh

dayu 100 ballov pomogite eto srochno dana posledovatelnost 13 3 10 2

pomogite s zadachej pliz dam 30 ballov najdi vektor s ravnyj raznosti vektorov a

pomogite soch po geometrii 50b dva ugla vpisannogo v okruzhnost chetyrehugolni

pomagite pozhalujstaac8f5e9a1906404bc4a1ecc85ad82d08 26247

100bpomogite vychislit zadache

pomogite pozhalujsta dam 70b 1 vypishite iz teksta vosklicatelnoe i voprositel

18 najdite shestoj n yj chlen etoj prgresii

рекомендуемые вопросы

Helpful Links

Helpful Social