`|{:(,1,(3pi)/(10),(2pi)/(10)),(,0,"cos"((3pi)/(10)),sin((2pi)/(10))),(,0,"sin"((3pi)/(10)),cos((2pi)/(10))):}|` का मान ज्ञात कीजिए |

Explanation

माना `Delta=|{:(1,(3pi)/(10),(2pi)/(10)),(0,cos((3pi)/(10)),sin((2pi)/(10))),(0,sin((3pi)/(10)),cos((2pi)/(10))):}|`
तब, `Delta=|{:(cos((3pi)/(10)),sin((2pi)/(10))),(sin((3pi)/(10)),cos((2pi)/(10))):}|`
[`C_(1)` के अनुदिश प्रसार करने पर]
`cos((3pi)/(10))cos((2pi)/(10))-sin((3pi)/(10))sin((2pi)/(10))`
`=cos((3pi)/(10)+(2pi)/(10))="cos"(pi)/(2)=0`