Cosine is co added onto sine. Basically, cosine is the sine function moved over 90degrees or pi/2 (pi/2 on a unit circle is 90 degrees)
Sin(x)=cos(x+90) <--degrees
Sin(x)=cos(x+pi/2) <--radians
The above two equations for converting them is called a cofunction identity. There's many more identities to convert sines, cosines, tangents, cosecantes, secantes, and cotangents between each other. This is taught to you in PreCalculus.
It would be 56 degrees since it's a vertical angle and to get the obtuse angles you just subtract 180 from 56 and there's your answer. Hope this helped! (':
Answer:
No, he is incorrect because he forgot to multiple the negative by the x, and only multiplied 3 by x instead of -3 by x.
Step-by-step explanation:
The correct re-write of this expression is:
-3x - 30
Answer:
10.26 in²
Step-by-step explanation:
The area (A) of the sector is
A = area of circle × fraction of circle
= πr² × 
= π × 2.8² × 
≈ 10.26 in²
