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.
Answer:
does this help
Step-by-step explanation:
A, it’s A. As both parties have negatives.
Answer:

Step-by-step explanation:
Given




Required
The perimeter
First, calculate the distance between each point using:

So, we have:




So, the perimeter (P) is:


The formula for the light bend would be n1*sin i= n2 * sin r
If you use "sin (90-x)= cos x" principle, you can change the sin in the equation into
n1*sin i= n2 * sin r
n1 * cos a= n2 * cos b
n2/n1= cos a/ cos b
Assuming the n constant is the ratio of the glass compared to water then the answer would be: cos a/ cos b