MCQ
$\sin2\text{A}=2\sin\text{A}$ is true when $A =$
- ✓$0^\circ$
- B$30^\circ$
- C$45^\circ$
- D$60^\circ$
✓
Answer
Correct option: A.
$0^\circ$
We are given $\sin2\text{A}=2\sin\text{A}.\cos\text{A}$
So,
$\Rightarrow\sin2\text{A}=2\sin\text{A}$
$\Rightarrow2\sin\text{A}.\cos\text{A}=2\sin\text{A}$
$\Rightarrow\cos\text{A}=1$
$\Rightarrow\cos\text{A}=\cos0^\circ$
As $\text{A}=0^\circ$
Hence the correct option is $(a)$
So,
$\Rightarrow\sin2\text{A}=2\sin\text{A}$
$\Rightarrow2\sin\text{A}.\cos\text{A}=2\sin\text{A}$
$\Rightarrow\cos\text{A}=1$
$\Rightarrow\cos\text{A}=\cos0^\circ$
As $\text{A}=0^\circ$
Hence the correct option is $(a)$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A vertical stick $1.8m$ long casts a shadow $45\ cm$ long on the ground. At the same time, what is the lenght of the shadow of a pole $6m$ high?
→A month is selected at random in a year. The probability that it is March or October, is:
The number of solid spheres, each of diameter $6\ cm$ that can be made by melting a solid metal cylinder of height $45\ cm$ and diameter $4\ cm$ is :
→It the roots of $a x^2+b x+c=0$ are real and equal then ______ .
→Two numbers $'a\ ’$ and $'6\ ’$ are selected successively without replacement in that order from the integers $1$ to $10.$ The probability that $\frac{\text{a}}{\text{b}}$ is an integer, is:
→$9\sec^2\text{A}-9\tan^2\text{A}$ is equal to:
→→
Select the appropriate alternative.
ΔABC and ΔDEF are equilateral triangles, A(ΔABC) : A(ΔDEF) = 1 : 2. If AB = 4 then what is length of DE?
ΔABC and ΔDEF are equilateral triangles, A(ΔABC) : A(ΔDEF) = 1 : 2. If AB = 4 then what is length of DE?
If $\sec\theta=\frac{25}{7}$ then $\sin\theta=?$
→A number $x$ is chosen at random from the numbers $-3, -2, -1, 0, 1, 2, 3$ the probability that $|x| < 2$ is:
→