isi-entrance 2021 Q27

isi-entrance · India · UGA Trig Proofs Extremal Value of Trigonometric Expression
If the maximum and minimum values of $\sin ^ { 6 } x + \cos ^ { 6 } x$, as $x$ takes all real values, are $a$ and $b$, respectively, then $a - b$ equals
(A) $\frac { 1 } { 2 }$.
(B) $\frac { 2 } { 3 }$.
(C) $\frac { 3 } { 4 }$.
(D) 1 .
If the maximum and minimum values of $\sin ^ { 6 } x + \cos ^ { 6 } x$, as $x$ takes all real values, are $a$ and $b$, respectively, then $a - b$ equals\\
(A) $\frac { 1 } { 2 }$.\\
(B) $\frac { 2 } { 3 }$.\\
(C) $\frac { 3 } { 4 }$.\\
(D) 1 .