Prove that
`|(-6,7),(-4,-9)| = 82`

Prove that (4cos^(2)9^(@)-3)(4cos^(2)7^(@)-3)=tan9^(@)

Prove that, cot 7 1/2 ^@ or tan 82 1/2 ^@ = (sqrt(3)+sqrt(2))(sqrt(2)+1) or sqrt(2)+sqrt(3)+sqrt(4)+sqrt(6)

If x+(1)/(x)=a then prove that x^(6)+(1)/(x^(6)) =a^(6)-6a^(4) +9a^(2)-2 .

Prove that (1)8P_(3)=7P_(3)+3.7P_(2) and (2)9P_(4)+4.9P_(4)=10P_(4)

Proved that (2)/(3)times[(-6)/(7)times(4)/(5)]=[(2)/(3)times(4)/(5)]times((-6)/(7))

the mode of the data 8, 4, 5, 3, 6, 7, 7, 8, 4, 6, 8, 9 and 9 is 7.

Prove that: sin((4 pi)/(9)+7)cos((pi)/(9)+7)-cos((4 pi)/(9)+7)sin((pi)/(9)+7)=(sqrt(3))/(2)

Prove that the straight lines 4x+7y=9, 5x-8y+15=0 and 9x-y+6=0 are concurrent.