So the root number 7sinc of sinc=3.

Because (sinc) 2+(cosc) 2 = 1, it is substituted into the root number 7sinc with sinc=3.

De (3 radicals 7 SINC) 2+(COSC) 2 = 1

Cosc= plus or minus 1/8.

Because in triangle 0; 0

So in the first quadrant,

So cosc= 1/8.