Question

Помогите пожалуйста . Номера 15,16,17

Answer 1

1.
$(tg a+ctga)*sin2a$=$(frac{sin a}{cos a} + frac{cosa}{sina} )*2sin alpha cos alpha =( frac{sin^2a+cos^2a}{sina*cosa} )*2sinacosa=$$( frac{1}{sinacosa} )*2sinacosa=2$
2.
sin(arcsin1/2+arccos1/2)=sin(arcsin1/2)*cos(arccos1/2)+cos(arcsin1/2)*sin(arccos1/2)=1/2*1/2+cos(arcsin1/2)*sin(arccos1/2)=1/4+cos(arcsin1/2)*sin(arccos1/2)=1/4+√(1-sin²(arcsin1/2))*√(1-cos²(arccos1/2))=1/4+√(1-1/4)*√(1-1/4)=1/4+√3/2*√3/2=1/4+3/4=1
3.
sinx=0.6525
x=$(-1)^{k}$*arcsin(0.6525)+πk,k∈Z