Download App

Trigonometry – II — Maths STD 11 Science — Question

Maharashtra BoardEnglish MediumSTD 11 ScienceMathsTrigonometry – II2 Marks
MCQ
$1+\cos 2 x+\cos 4 x+\cos 6 x=$
  • A
    $2 \cos x \cos 2 x \cos 3 x$
  • B
    $4 \sin x \cos 2 x \cos 3 x$
  • ✓
    $4 \cos x \cos 2 x \cos 3 x$
  • D
    $2 \sin x \cos 2 x \cos 3 x$
✓

Answer

Correct option: C.
$4 \cos x \cos 2 x \cos 3 x$
(C)
$1+\cos 2 x+\cos 4 x+\cos 6 x$
$=(1+\cos 6 x)+(\cos 2 x+\cos 4 x)$
$=2 \cos ^2 3 x+2 \cos 3 x \cos x$
$=2 \cos 3 x(\cos 3 x+\cos x)$
$=4 \cos x \cos 2 x \cos 3 x$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "MCQ" from Trigonometry – II→Trigonometry – II — all question types→Maths STD 11 Science question papers→Maharashtra Board STD 11 Science question papers→Maharashtra Board question paper generator→

Similar questions

If $\lim _{x \rightarrow 0} \frac{\cos 4 x+ a \cos 2 x+ b }{x^4}$ is finite, then $( a , b )$ =
→
If a is any real number, the number of roots of $\cot\text{x}-\tan\text{x}=\text{a}$ in the first quadrant is $($are$)$ :
→
If there are 10 values each equal to 10, then S.D. of these values is _________
→
$\lim _{x \rightarrow \infty} x^3\left\{\sqrt{x^2+\sqrt{1+x^4}}-x \sqrt{2}\right\}=$
→
Which of the following statements is false :
→
If $\text{z}=\frac{-2}{1+\sqrt{3}},$ then the value of arg $(z)$ is :
→
If $a>0$ and $z=\frac{(1+i)^2}{a-i}, i=\sqrt{-1}$, has magnitude $\frac{2}{\sqrt{5}}$, then $\bar{z}$ is
→
If $f (x)=\frac{2 x-1}{x+5}(x \neq 5)$, then $f ^{-1}(x)$ is equal to
→
$\frac{1-\tan2^{\circ}\cot62^{\circ}}{\tan152^{\circ}-\cot88^{\circ}}=$
→
If $\cos \theta=\frac{8}{17}$ and $\theta$ lies in the $1^{\text {st }}$ quadrant, then the value of
$\cos \left(30^{\circ}+\theta\right)+\cos \left(45^{\circ}-\theta\right)+\cos \left(120^{\circ}-\theta\right)$ is
→