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If alpha and beta respectively the minmu...

If `alpha and beta` respectively the minmum and minimum values of the fuction f(x) given by
`f(x)=|{:(1+sin^2" " x cos^2x " " sin2x),(sin^2x " "1+cos^2 x " "sin 2x),(sin^2x " "cos^2x" "1+sin 2x):}|` then which one of
the following options is not true ?

A

`alpha+ beta^9=4`

B

`alpha ^3 - beta ^7 =26`

C

`alpha^(2n)-beta ^(2n)` is always and even integer for `n in N`

D

a triangle can be costructed having its sides as `alpha , beta and alpha- beta`

Text Solution

Verified by Experts

The correct Answer is:
D

Applying `C_ 1 rarr C+ C_2` we get
`f(x)=|{:(1+sin^2" " x cos^2x " " sin2x),(sin^2x " "1+cos^2 x " "sin 2x),(sin^2x " "cos^2x" "1+sin 2x):}|`
`=|(2 " "cos^x " " sin 2x),(0" "1 " "0),(-1 " "0" "1)| " " " Applying " R_2 rarr R_2-R_1 and R_3 rArr R_3-R_1`
`=2+ sin 2x `
We know that
`-1 le sin 2x le 1 " for all " x`
`rArr 1 le 2 + sin 2x le 3 " for all " x `
`rArr 1 le f(x) le 3 "for all " x`
`rArr alpha =3 and beta =1`
Clearly , these values of `alpha and beta` satisfy (a),(b) and (c)
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