Question

If 2cos +sin = 1 ( ≠ 2 ), then 7cos + 6sin is equal to

Answer 1

Answer:

7cos + 6sin = 6

Step-by-step explanation:

Gn:

2cos + sin = 1

To find: 7cos + 6sin

2cos + sin = 1

if ∠ is 90 only,

2cos90 + sin90 = 1

2(0) + 1 = 1

0 + 1 = 1

therefore, ∠ is 90 ...... (1)

2cos + sin = 1

sin = 1 - 2 cos ...... (2)

7cos + 6sin

= 7cos + 6(1- 2cos) [substituting (2)]

= 7cos + 6 - 12cos

= 6 - 5cos

= 6 - 5cos90 [substituting (1)]

= 6 - 5(0)

= 6 - 0

= 6