Question

Cos 6theta + cos 4theta + cos 2theta +1=0,0degree theta to 180 degree

Answer 1

Answer:

this question will have 3 cases each case having its own different answer

Step-by-step explanation:

I HAVE DENOTED THETA BY @

=>COS6@+COS4@+COS2@+1=0

=>2COS(6@+4@/2)COS(6@-4@/2)+COS2@+1=0

=>2COS5@COS@+2COS²@-1+1=0

=>2COS5@COS@+2COS²@=0

=>2COS@(COS5@+COS@)=0

NOW VARIOUS CASES ARISE FROM THIS EQUATION

=>

CASE1:

2COS@=0

COS@=0

X=(2n+1)PI/2

CASE2:

COS5@+COS@=0

2COS3@COS2@=0

NOW THERE ARE 2 SUB PARTS OF THIS CASE

1ST SUB PART:

WHEN,

2COS3@=0

COS3@=0

3@=(2n+1)PI/2

@=(2n+1)PI/6

2ND SUB PART:

WHEN,

COS2@=0

2@=(2n+1)PI/2

@=(2n+1)PI/2