A)cos^{2}α -1/3-3sin^{2} α б)4/sin^{2}α - 4 ctg^{2}α

Question

A)cos^{2}α -1/3-3sin^{2} α
б)4/sin^{2}α - 4 ctg^{2}α

Answer 1

Cos²a-1/3-3sin²a=1-sin²a-1/3-3sin²a=2/3-4sin²a
4/sin²a-4ctg²a=4/sin²a-4(1/sin²a-1)=4/sin²a-4/sin²a+4=4