Which of the following is not an identity for ?

a.
`(1 - cos x)/(sin x)`

b.
`(sin x)/(1 + cos x)`

c.
`(cos x)/(1-sin x)`

d.
`+- sqrt((1 - cosx)/(1 + cos x))`

If 90° < θ < 180° and cotθ = -1/3, then cscθ =

Twenty-five percent of the customers entering a grocery store between 5 p.m. and 7 p.m. use an express checkout. consider five randomly selected customers, and let x denote the number among the five who use the express checkout.

How to use order of operation in 20 divide by 4 multiply 5 = 1