Question

aplicando a fórmula de adição e subtraçõa de arcos calcule o valor;
cos75,seno15°,cos15°,sen105° e cos105°

Answer 1

cos(30+45)= cos30.cos45 - sen30.sen45= √3/2.√2/2 -1/2.√2/2= √6/4- √2/4=(√6-√2)/4
sen(45-30)=sen45.cos30- sen30.cos45=√2/2.√3/2-1/2.√2/2=√6/4-√2/4=(√6-√2)/4
cos(45-30)=cos45.cos30+sen45.sen30=√2/2.√3/2+√2/2.1/2=√6/4-√2/4=(√6+√2)/4
sen(60+45)=sen60.cos45+sen45.cos60=√3/2.√2/2+√2/2.1/2=√6/4+√2/4=(√6+√2)/4
cos(60+45)=cos60.cos45-sen60.sen45=1/2.√2/2-√3/2.√2/2=√2/4-√6/4=(√2-√6)/4