Answer:
[tex]\left(1 - \sin^{2}(x)\right)^{2}[/tex].
Step-by-step explanation:
Notice that "[tex]1[/tex]" is equal to "[tex]1^{2}[/tex]" whereas [tex]\sin^{4}(x) = {\left(\sin^{2}(x)\right)}^{2}[/tex]. Therefore:
[tex]\begin{aligned} & 1 - 2\, \sin^{2}(x) + \sin^{4}(x) \\ =\; & 1^{2} - 2\, \sin^{2}(x) + {\left(\sin^{2}(x)\right)}^{2}\end{aligned}[/tex].
Make use of the identity [tex](a - b)^{2} = a^{2} - 2\, a\, b + b^{2}[/tex]. In this case, set [tex]a = 1[/tex] whereas [tex]b = \sin^{2}(x)[/tex]. Therefore:
[tex]\begin{aligned} & 1^{2} - 2\, \sin^{2}(x) + {\left(\sin^{2}(x)\right)}^{2} \\ =\; & a^{2} - 2\, a\, b + b^{2} \\ =\; & (a - b)^{2} \\ =\; & {\left(1 - \sin^{2}(x)\right)}^{2}\end{aligned}[/tex].
