1.

tanα = a/b then the value of Sinα + Cosα is:1. \(\sqrt{a^2 + b^2} \over {a + b}\)2. \({a + b} \over \sqrt{a^2 + b^2}\)3. \(\sqrt{a^2 - b^2} \over {a + b}\)4. \({a + b} \over \sqrt{a^2 - b^2}\)

Answer» Correct Answer - Option 2 : \({a + b} \over \sqrt{a^2 + b^2}\)

Given:

tanα = a/b

Concept Used:

tanθ = Perpendicular/Base

Sinθ = Perpendicular/Hypotenuse

Cosθ = Base/Hypotenuse

Base2 + Perpendicular2 = Hypotenuse2

Calculation:

tanα = a/b

and tanα = Perpendicular/Base

Comparing above two get,

Perpendicular = a and Base = b

Hypotenuse = √a2 + b2

Sinα = Perpendicular/Hypotenuse

⇒ Sinθ = a/√a2 + b2

Cosα = Base/Hypotenuse

⇒ Cosα = b/√a2 + b2

Sinα + Cosα =  (a/√a2 + b2) + (b/√a2 + b2)

⇒ Sinα + Cosα = \({a + b} \over \sqrt{a^2 + b^2}\)

∴ Sinα + Cosα = \({a + b} \over \sqrt{a^2 + b^2}\)



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