Answer:
[tex]10!\:\times \:20!=\:8.82851\:\times\:10^{24}[/tex]
[tex]17!\:\times \:9!\:=\:1.29072\:\times \:10^{20}[/tex]
Step-by-step explanation:
1)
Given the expression
[tex]10!\times \:20![/tex]
[tex]\mathrm{Apply\:factorial\:rule}:\quad \:n!=1\times 2\times 3\times \ldots \times \:n[/tex]
[tex]10!=1\times \:2\times \:3\times \:4\times \:5\times \:6\times \:7\times \:8\times \:9\times \:10[/tex]
[tex]20!=1\times \:2\times \:3\times \:4\times \:5\times \:6\times \:7\times \:8\times \:9\times \:10\times \:11\times \:12\times \:13\times \:14\times \:15\times \:16\times \:17\times \:18\times \:19\times \:20[/tex]
Now, multiplying the result
[tex]10!\times \:20!= 1\times \:2\times \:3\times \:4\times \:5\times \:6\times \:7\times \:8\times \:9\times \:10\times \:1\times \:2\times \:3\times \:4\times \:5\times \:6\times \:7\times \:8\times \:9\times \:10\times \:11\times \:12\times \:13\times \:14\times \:15\times \:16\times \:17\times \:18\times \:19\times \:20[/tex]
so
[tex]10!\:\times \:20!=\:8.82851\:\times\:10^{24}[/tex]
Thus, we conclude that:
[tex]10!\:\times \:20!=\:8.82851\:\times\:10^{24}[/tex]
2)
Given the expression
[tex]17!\:\times \:9![/tex]
[tex]\mathrm{Apply\:factorial\:rule}:\quad \:n!=1\times 2\times 3\times \ldots \times \:n[/tex]
[tex]17!=1\times \:2\times \:3\times \:4\times \:5\times \:6\times \:7\times \:8\times \:9\times \:10\times \:11\times \:12\times \:13\times \:14\times \:15\times \:16\times \:17[/tex]
[tex]9!=1\times \:2\times \:3\times \:4\times \:5\times \:6\times \:7\times \:8\times \:9[/tex]
Now, multiplying the result
[tex]17!\:\times \:9!=1\times \:2\times \:3\times \:4\times \:5\times \:6\times \:7\times \:8\times \:9\times \:10\times \:11\times \:12\times \:13\times \:14\times \:15\times \:16\times \:17\times \:1\times \:2\times \:3\times \:4\times \:5\times \:6\times \:7\times \:8\times \:9[/tex]
so
[tex]17!\:\times \:9!\:=\:1.29072\:\times \:10^{20}[/tex]
Thus, we conclude that:
[tex]17!\:\times \:9!\:=\:1.29072\:\times \:10^{20}[/tex]
