To solve this expression, we need to find the values of cosine, sine, and tangent of the given angles.
Cos 225° = -√2/2Sin 405° = -√2/2Tg 420° = 1
Now, substitute the values into the expression:
-√2/2 + (-√2/2) + 1 = -√2
Therefore, Cos 225° + Sin 405° + Tg 420° = -√2
To solve this expression, we need to find the values of cosine, sine, and tangent of the given angles.
Cos 225° = -√2/2
Sin 405° = -√2/2
Tg 420° = 1
Now, substitute the values into the expression:
-√2/2 + (-√2/2) + 1 = -√2
Therefore, Cos 225° + Sin 405° + Tg 420° = -√2