In an isosceles triangle A BC with ∠ A = 10 0 ∘ , let x = sin A + sin B + sin C and y = cos A + cos B + cos C . Find x 2 + y 2 .

B = C = 4 0 ∘ . Expanding gives 3 + 2 [ cos 6 0 ∘ + cos 0 ∘ + cos ( − 6 0 ∘ ) ] = 7 .

Mathematics - Properties of Triangle Question with Solution | TestHub

MathematicsProperties of TriangleGeneral (basic formula based)Medium3 minQB

MathematicsMediuminteger

In an isosceles triangle $A BC$ with $∠ A = 10 0^{\circ}$ , let $x = sin A + sin B + sin C$ and $y = cos A + cos B + cos C$ . Find $x^{2} + y^{2}$ .

Answer:

Solution:

$B = C = 4 0^{\circ}$ . Expanding gives $3 + 2 [cos 6 0^{\circ} + cos 0^{\circ} + cos (- 6 0^{\circ})] = 7$ .

Stream:JEESubject:MathematicsTopic:Properties of TriangleSubtopic:General (basic formula based)

⏱ 3mℹ️ Source: QB

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