RRB Group-D Model Paper 11 with answers for online practice

© examsiri.com

Question : 95 of 100

Marks: +1, -0

(1 - sinA)^2 + (1 + sinA)^2 + (1 - cosA)^2 + (1 + cosA)^2

is equal to

√2
1/2
2
6

Solution:

(1 - sinA)^2 + (1 + sinA)^2 + (1 - cosA)^2 + (1 + cosA)^2

⇒

1 + sin^2A – 2 sinA + 1 + sin^2A + 2 sinA + 1 + cos^2A – 2 cosA + 1 + cos^2A + 2 cosA (∵ (a ± b)^2 = a^2 ± 2ab + b^2)

⇒

1 + sin^2A + 1 + sin^2A + 1 + cos^2A + 1 + cos^2A

⇒ 4 +

2 (sin^2A + cos^2A)

⇒ 4 + 2 = 6 (∵

sin^2A + cos^2A

= 1)

© examsiri.com

Go to Question:

Prev Question

Next Question