Q18 of 123 Page 9

Mark the Correct alternative in the following:

The value of is equal to


Given expression is


Consider



[using the formulae cos 3x = 4 cos3 x – 3 cos x and


cos 2x = 2cos2x -1]




= cos x


Therefore


Hence the answer is option A.

More from this chapter

All 123 →
16

Mark the Correct alternative in the following:

The value of 2 cos x – cos 3x – cos 5x – 16 cos3 x sin2 x is


 17

Mark the Correct alternative in the following:

If A = 2 sin2 x – cos 2x, then A lies in the interval


 19

Mark the Correct alternative in the following:

If tan (/4 + x) + tan (/4 – x) = λ sec 2x, then


 20

Mark the Correct alternative in the following:

The value of is