Answer:
[tex](1-cos^2 x ).(1+tan^2 x) = tan^2x[/tex]
Step-by-step explanation:
Given
[tex](1-cos^2 x ).(1+tan^2 x)[/tex]
Required
Solve
[tex](1-cos^2 x ).(1+tan^2 x)[/tex]
In trigonometry;
[tex]1 - cos^2x = sin^2x[/tex]
So, make substitution
[tex](1-cos^2 x ).(1+tan^2 x)[/tex] becomes
[tex](1-cos^2 x ).(1+tan^2 x) = (sin^2 x ).(1+tan^2 x)[/tex]
Also; in trigonometry:
[tex]1 + tan^2x = sec^2x[/tex]
Make another substitution
[tex](1-cos^2 x ).(1+tan^2 x) = (sin^2 x ).(sec^2 x)[/tex]
Recall that [tex]secx = \frac{1}{cosx}[/tex]
So;
[tex](1-cos^2 x ).(1+tan^2 x) = (sin^2 x ).(sec^2 x)[/tex] becomes
[tex](1-cos^2 x ).(1+tan^2 x) = (sin^2 x ).(\frac{1}{cos^2 x})[/tex]
[tex](1-cos^2 x ).(1+tan^2 x) = \frac{sin^2 x }{cos^2 x}[/tex]
[tex](1-cos^2 x ).(1+tan^2 x) = (\frac{sin x }{cosx})^2[/tex]
In trigonometry;
[tex]tan x = \frac{sin x}{cos x}[/tex]
[tex](1-cos^2 x ).(1+tan^2 x) = tan^2x[/tex]
The expression cannot be further simplified
