1
NDA 2019 Paper 1
MCQ (Single Correct Answer)
+2.5
-0.83
Read the given information carefully and answer the given questions.

It is given that $$\cos (\theta - \alpha ) = a$$, $$\cos (\theta - \beta ) = b$$.
What is $$\cos (\alpha - \beta )$$ equal to?
A
$$ab + \sqrt {1 - {a^2}} \sqrt {1 - {b^2}} $$
B
$$ab - \sqrt {1 - {a^2}} \sqrt {1 - {b^2}} $$
C
$$a\sqrt {1 - {b^2}} - b\sqrt {1 - {a^2}} $$
D
$$a\sqrt {1 - {b^2}} + b\sqrt {1 - {a^2}} $$
2
NDA 2019 Paper 1
MCQ (Single Correct Answer)
+2.5
-0.83
Read the given information carefully and answer the given questions.

It is given that $$\cos (\theta - \alpha ) = a$$, $$\cos (\theta - \beta ) = b$$.
What is $${\sin ^2}(\alpha - \beta ) + 2ab\cos (\alpha - \beta )$$ equal to?
A
a2 + b2
B
a2 $$-$$ b2
C
b2 $$-$$ a2
D
$$-$$ (a2 + b2)
3
NDA 2019 Paper 1
MCQ (Single Correct Answer)
+2.5
-0.83
If $$\sin \alpha + \cos \alpha = p$$, then what is $${\cos ^2}(2\alpha )$$ equal to?
A
p2
B
p2 $$-$$ 1
C
p2 (2 $$-$$ p2)
D
p2 + 1
4
NDA 2019 Paper 1
MCQ (Single Correct Answer)
+2.5
-0.83
If $$\tan \theta = {1 \over 2}$$ and $$\tan \phi = {1 \over 3}$$, then what is the value of $$(\theta + \phi )$$ ?
A
0
B
$${\pi \over 6}$$
C
$${\pi \over 4}$$
D
$${\pi \over 2}$$
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12