Question

1)cos⁴ - sin⁴ x=
2) cos 2254°=
3) tan 45° cot 30° : -tan30° cot 45
4) tan 225° - cot225° + tan60° - 2 cot120°

Answer 1

1) cos^4 x - sin^4 x = (cos^2 x + sin^2 x) (cos^2 x - sin^2x ) = 1 x (cos 2x) = cos 2x 2) cos 2254 2254 mod 360 = 94 cos 2254 = cos 94 = -cos 86 = -0,997.... 3) 1 x akar 3/-1/3 akar 3 x 1 = -3 4) tan 45 - cot 45 + tan 60 - 2 cot 60 = tan 60 + 2 cot 60 = akar 3 + 2/3 akar 3 = 5/3 akar 3 Semoga membantu :)