Question

Express (cos θ - sin θ) as a cosine of an angle.

Answer 1

(cosθ - sinθ) = √2(1/√2 . cosθ - 1/√2. sinθ)

we know, cos45° = 1/√2

and sin45° = 1/√2

= 2(cos45° . cosθ - sin45° . sinθ)

we know, formula cos(A + B) = cosA.cosB - sinA. sinB

so, cos45° . cosθ - sin45° . sinθ = cos(45° + θ)


hence, (cosθ - sinθ) = √2cos(45° + θ)

Answer 2

Answer:

Step-by-step explanation:

Best explanation