Question

solve cos x cos 2x cos 3x=1/4​

Answer 1

Answer:

Step-by-step explanation:

cosxcos2xcos3x=1/4

1/2(cos2x+cos4x)cos 3x=1/4

cos3x(cos2x+cos4x)=1/2

cos3xcos2x+cos3xcos4x=1/2

cos6x+cos4x+cos6x+cos8x=1/2

2cos6x+cos4x+cos8x=1/2

x=1.45