1)i heard this news b)have 2)my uncle languagesb)speaks 3.open the brackets and put the verb in the correct form.1)john is working very hard at the moment.2)when they finished their work, they went home.3)what did you do last week? 4.fill in the blanks with the following modal verbs: can,could,must,may,should.1)she should get up early in the morning 2)ann can sing,dance and draw.3)you must cross the street when the light is green 4)could you pass me a scone,please? 5) may i ask you a question?
ответ:
пошаговое объяснение:
sin²x+2sinx cosx=3cos²x
sin²x +2sinx cosx-3cos²x=0
tg²x + 2tgx -3=0
пусть tgx=y
y²+2y-3=0
d=4+12=16
y₁=-2-4=-3
y₂=-2+4=1
при у=-3
tgx=-3
x=-arctg3+πn, n∈z
при у=1
tgx=π/4 +πn, n∈z
ответ: х=-arctg3 +πn, n∈z ; x=π/4 +πn, n∈z.