Download App

Introduction of Trigonometry and its Application — Maths STD 10 — Question

CBSE BoardEnglish MediumSTD 10MathsIntroduction of Trigonometry and its Application1 Mark
MCQ
Choose the correct answer from the given four options.
If $\triangle\text{ABC}$ is right angled at C, then the value of $\cos\text{(A+ B)}$ is:
  • ✓
    $0$
  • B
    $1$
  • C
    $\frac{1}{2}$
  • D
    $\frac{\sqrt{3}}{2}$
✓

Answer

Correct option: A.
$0$
We know that, in $\triangle\text{ABC,}$ sum of three angles = 180º
$\text{i.e., }\angle\text{A}+\angle\text{B}+\angle\text{C}=180^\circ$
But right angled at C. i.e., $\angle\text{C}=90^\circ$ [given]
$\angle\text{A}+\angle\text{B}+90^\circ=180^\circ$
$\Rightarrow\ \ \text{A}+\text{B}=90^\circ$ $[\because\angle\text{A}=\text{A}]$
$\therefore\ \ \cos(\text{A}+\text{B})=\cos90^\circ=0$

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 "M.C.Q (1 Marks)" from Introduction of Trigonometry and its Application→Introduction of Trigonometry and its Application — all question types→Maths STD 10 question papers→CBSE Board STD 10 question papers→CBSE Board question paper generator→

Similar questions

The distance between the points $(3, -2)$ and $(-3, 2)$ is:
→
A set of points equidistant from a fixed point in a plane figure is called :
→
The distance of the point (4, 7) from the y-axis is
→
In a right triangle $\text{ABC}, \angle\text{C}=90^\circ.$ If $\text{AC}=\sqrt3 BC$ and $ \angle\text{B}=\phi,$ then find its value.
→
The marks obtained by $9$ students in Mathematics are $\{59, 46, 31, 23, 27, 44, 52, 40\}$ and $29$. The mean of the data is :
→
Choose the correct answer from the given four options : Which term of the $AP : \{21, 42, 63, 84,........\}$ is $210?$
→
If a chord of a circle of radius $r$ subtends a right angle at the centre of the circle, then the area of the corresponding segment of the circle is
→
$\frac{\cot\theta}{\cot\theta-\cot3\theta}+\frac{\tan\theta}{\tan\theta-\tan3\theta}$ is equal to:
→
Choose the correct answer from the given four options :
It is given that $\triangle\text{ABC}\sim\triangle\text{DEF},\ \angle\text{A}=30^\circ,\ \angle\text{C}=50^\circ,$ $AB = 5\ cm, AC = 8\ cm,$ and $DF = 7.5\ cm $ Then, the following is true:
→
$ (+\sqrt{2})+(-1\sqrt{2})$ is
→