Answer :

sulaman2003tar

Step-by-step explanation:

Given sinA – cosA = 1/2 squaring on both the sides, we get (sinA – cosA)2 = (1/2)2 ⇒ sin2A + cos2A – 2sinA cosA = 1/4 ⇒ 1 – 2sinA cosA = 1/4 ⇒ 1 – (1/4) = 2sinA cosA ⇒ 2sinA cosA = 3/4 ∴ sinA cosA = 3/8  → (1) (sinA + cosA)2 = (sinA – cosA)2 + 4sinA cosA                         = (1/2)2 + 4(3/8)                         = (1/4) + (3/2) = 7/4 (sinA + cosA) = √(7/4) = (√7)/2 .

loneguy

Given that,

[tex]\sin A = \dfrac 12\\\\ \implies \sin^2 A = \dfrac 14\\\\\ \implies 1-\cos^2 A = \dfrac 14\\\\\ \implies \cos^2 A = 1 - \dfrac 14 = \dfrac 34\\\\\ \implies \cos A = \pm \dfrac{\sqrt 3}2\\\\\text{Case 1:}\\\\\sin A + \cos A = \dfrac 12 + \dfrac{\sqrt 3}2 = \dfrac{1 + \sqrt 3}2\\\\\text{Case 2:}\\\\\sin A + \cos A = \dfrac 12 +\left(- \dfrac{\sqrt 3}2\right) = \dfrac 12 - \dfrac{\sqrt 3}2=\dfrac{1 - \sqrt 3}2[/tex]

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