Question

The maximum value of sin(4 cos³x - cos 3x) is -​

Answer 1

Answer:

Step-by-step explanation:

Correct option is

A

1

f(x)=sin  

3

x+cos  

3

x

f  

′

 

(x)=3sin  

2

xcosx−3cos  

2

xsinx=0

3sinxcosx(sinx−cosx)=0

It can also be written as  

(3/2)sin2x(sinx−cosx)=0

sin2x=0 or sinx−cosx=0

x=π/4

Check for second derivative

3(2sinxcos  

2

x+sin  

2

x(−sinx))−3(cos  

2

xcosx+2cosx(−sinx)sinx)

(2sinxcos  

2

x−sin  

3

x−cos  

3

x+2sin  

2

xcosx)

Putsinx=1/  

2

​

, cosx=1/  

2

​

 

=  

2

​

−1/  

2

​

>0

Therefore sin2x=0will give maximum

2x=nπ

x=nπ/2

Take value of n=1

x=π/2

f(x)=sin  

3

(π/2)+cos  

3

(π/2)=1

Answer 2

Answer:

ans = 0.69

Step-by-step explanation:

0.06974589581