Question

cos( 3π\4+x) - cos ( 3π\4-x) = -√2 sinx

Answer 1

Step-by-step explanation:

l.h.s

= cos(3π\4+x)-cos(3π\4-x)

= -2sin{(3π\4+x) + (3π\4 - x)} .sin{(3π\4+x)-(3π\4-x) }

2 2

= -2sin(3π\4)sinx

= -2sin(π-π\4)sinx

= -2sinπ\4sinx

= -2*1 * sinx

√2

= -√2sinx

= r.h.s