Prove Trigonometric Identities

Trigonometry equalities, inequalities and expressions - sin, cos, tan, cot

Prove Trigonometric Identities

Postby nycmath » Sat Sep 26, 2026 4:48 am

See attachment.
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Re: Prove Trigonometric Identities

Postby Eigenvalue » Sat Sep 26, 2026 12:31 pm

[tex]\frac{cos(x)}{1-sin(x)}[/tex]=[tex]\frac{1+sin(x)}{cos(x)}[/tex]

Cross multiply:
cos²(x)=(1+sin(x))(1-sin(x))

Use difference of squares to simplify:
cos²(x)=1-sin²(x)

Add sin²(x) to both sides:
sin²(x)+cos²(x)=1

sin²(x)+cos²(x)=1 is a Pythagorean identity
1=1

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