Olá,
[tex3]f(x) = sen^{2}x - cosx[/tex3]
[tex3]f'(x) = 2sen \, x \times \cos x + sen \, x[/tex3]
[tex3]f'(x) = sen \, 2x + sen \, x[/tex3]
[tex3]f''(x) = 2[(sen \, x)'\cos x + (\cos x)'sen \, x] + (sen \, x)'[/tex3]
[tex3]f''(x) = 2[\cos^2x - sen^2x] + \cos x[/tex3]...