To answer this you need to divide the total by 4 so 28 divided by four is 7 and 7*3=21 so Sam has 21 pencil erasers
Answer:
20,45
Step-by-step explanation:
Tanx sinx (cos^2x cscx- sinx)
=(sinx/cosx)((cos^2x cscx- sinx)
=(sinx/cosx)((cos^2x 1/sinx- sinx)
=(sinx/cosx)((cos^²x - sin²x)] / sinx
=(sinx/cosx)((cos^²x - sin²x)] / sinx
=(1/cosx)((cos^²x - sin²x)]
=(1/cosx)(2cos²x====> = 2 cos x]