Question

Pl solve this its urgent ​

Answer 1

Step-by-step explanation:

1)sin(-405°)=-1/√2

sin negative in fourth quadrant

Answer 2

Step-by-step explanation:

Pure calcium carbonate can be produced from marble, or it can be prepared by passing carbon dioxide into a solution of calcium hydroxide. In the later case calcium carbonate is derived from the mixture, forming a grade of product called "precipitated calcium carbonate,” or PCC.