prove cosh 3x=4 cosh^3x-3cosh
Answers
Answered by
12
cos (3x) = cos (2x + x)
=cos 2x cos x - sin 2x sin x
=cos 2x cos x - 2 sin ² x cos x
=cos 2x cos x - 2 cos x (1 - cos ² x)
=(2 cos ² x - 1) (cos x) + 2(cos ² x - 1))(cos x)
=2 cos ³ x - cos x + 2 cos ³ x - 2 cos x
===4 cos ³ x - 3 cos x
ɦօքɛ ɨt ɦɛʟքs !!!!
=cos 2x cos x - sin 2x sin x
=cos 2x cos x - 2 sin ² x cos x
=cos 2x cos x - 2 cos x (1 - cos ² x)
=(2 cos ² x - 1) (cos x) + 2(cos ² x - 1))(cos x)
=2 cos ³ x - cos x + 2 cos ³ x - 2 cos x
===4 cos ³ x - 3 cos x
ɦօքɛ ɨt ɦɛʟքs !!!!
Similar questions