Find dy/dx if. y = inverse of cos x

dy/dx = -1 /√(1 - x^2).

Step-by-step explanation:

y = arccos x.

So x  = cos y

dx / dy = - sin y

dy / dx = -1 / sin y

But sin y = √( 1 - cos^2 y)

But cos y = x , so cos^2y = x^2

Therefore  

dy/dx = -1 / √(1 - x^2).

.24

step-by-step explanation:

the probability is   .24

the first player had the highest probability of getting a silver marble

the game could be made fair by adding back the marble that was drawn after each draw