Using the database table below, I would like to write relational algebra and SQL queries for the following:

1. List all manufacturers who make PCs.

2) List the models and prices of all Laptops with the most expensive first.

3) List the model and price of the Laptops with more than 512 KB RAM and faster than 1.60.

4) List the model and manufacturer of all Laptops costing less than $ 1,000.

5) List the names and models of the manufacturers who make both PCs and laptops with speeds greater than 2.

6) Which manufacturers make PCs, but not printers?

Product

Product.maker	Product.model	Product.type
A	1001	pc
A	1002	pc
A	1003	pc
A	2004	laptop
A	2005	laptop
A	2006	laptop
B	1004	pc
B	1005	pc
B	1006	pc
B	2007	pc
C	1007	pc
D	1008	pc
D	1009	pc
D	1010	pc
D	3004	printer
D	3005	printer
E	1011	pc
E	1012	pc
E	1013	pc
E	2001	laptop
E	2002	laptop
E	2003	laptop
E	3001	printer
E	3002	printer
E	3003	printer
F	2008	laptop
F	2009	laptop
G	2010	laptop
H	3006	printer
H	3007	printer

PC

PC.model	PC.speed	PC.ram	PC.hd	PC.price
1001	2.66	1024	250	2114
1002	2.1	512	250	995
1003	1.42	512	80	478
1004	2.8	1024	250	649
1005	3.2	512	250	630
1006	3.2	1024	320	1049
1007	2.2	1024	200	510
1008	2.2	2048	250	770
1009	2	1024	250	650
1010	2.8	2048	300	770
1011	1.86	2048	160	959
1012	2.8	1024	160	649
1013	3.06	512	80	529

Laptop

Laptop.model	Laptop.speed	Laptop.ram	Laptop.hd	Laptop.screen	Laptop.price
2001	2	2048	240	20.1	3673
2002	1.73	1024	80	17	949
2003	1.8	512	60	15.4	549
2004	2	512	60	13.3	1150
2005	2.16	1024	120	17	2500
2006	2	2048	80	15.4	1700
2007	1.83	1024	120	13.3	1429
2008	1.6	1024	100	15.4	900
2009	1.6	512	80	14.1	680
2010	2	2048	160	15.4	2300

Printer

Printer.model	Printer.color	Printer.type	Printer.price
3001	true	ink-jet	99
3002	false	laser	239
3003	true	laser	899
3004	true	ink-jet	120
3005	false	laser	120
3006	true	ink-jet	100
3007	true	laser	200