2007-10-23 06:08:23 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
It isn't true.
(cos x - sin x)^2 = 1 - sin 2x, and this can only equal sin 2x if
sin 2x = 1/2.
This is when x = pi/12 or 5 pi/12 (mod pi).
2007-10-23 06:18:49 · answer #1 · answered by acafrao341 5 · 0⤊ 0⤋
not true
sin 2x = 2 six *cosx
and (cosx-sinx)^2 = cos^2x +sin^2x -2sin x *cos x= 1-sin 2x
so sin 2x not equal 1-sin 2x
2007-10-23 13:16:28 · answer #2 · answered by santmann2002 7 · 0⤊ 0⤋
RHS
(cosx - sinx)^2 = cos^2x + sin^2x - 2sinxcosx
=>1 - sin(2x)
2007-10-23 13:15:57 · answer #3 · answered by mohanrao d 7 · 0⤊ 0⤋
(cosx-sinx)^2=cosx^2-2cosxsinx+sinx^2
cosx^2+sinx^2=1
1-2cosxsinx=sin2x
2007-10-23 13:14:58 · answer #4 · answered by bubu_bus2003 1 · 0⤊ 0⤋
sin (2x)=-2sin(x)cos(x)
(cos (x) - sin (x) )^2 = cos^2(x)+sin^2(x)-2sin(x)cos(x)
=1-2sin(x)cos(x)
Is your question correct?
2007-10-23 13:16:06 · answer #5 · answered by cidyah 7 · 0⤊ 0⤋