3sina+4cosa=5 then find 3cosa-4sina

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?

43lbs of tomatos cost $387. how much would 41lbs cost

Find the values of y: 3y^3(y^2+ 2/3y)=0