ExamBro
ExamBro
AP EAMCET · Maths · Trigonometric Ratios & Identities

If \(\cos \alpha+\cos \beta=a\) and \(\sin \alpha+\sin \beta=b\), then match the items given in List \(-A\) with those of their values in List-B
List-ALiat-B
(I) \(\tan \left(\frac{\alpha+\beta}{2}\right)=\)(a) \(\frac{ b }{ a }\)
(II) \(\cos (\alpha+\beta)=\)(b) \(\frac{2 a b}{a^2+b^2}\)
(III) \(\sin (\alpha+\beta)^{-}\)(c) \(\frac{2 a b}{a^2-b^2}\)
(IV) \(\tan (\alpha+\beta)=\)(d) \(\frac{a^2-b^2}{a^2+b^2}\)
(e) \(\frac{a^2+b^2}{a^2-b^2}\)

  1. A (I) \(\rightarrow\) (a), (II) \(\rightarrow\) (e), (III) \(\rightarrow\) (d), (IV) \(\rightarrow\) (c)
  2. B (I) \(\rightarrow\) (a), (II) \(\rightarrow\) (c), (III) \(\rightarrow\) (b), (IV) \(\rightarrow\) (e)
  3. C (I) \(\rightarrow\) (a), (II) \(\rightarrow\) (d), (III) \(\rightarrow\) (c), (IV) \(\rightarrow\) (b)
  4. D (I) \(\rightarrow\) (a), (II) \(\rightarrow\) (d), (III) \(\rightarrow\) (b), (IV) \(\rightarrow\) (c)
Verified Solution

Answer & Solution

Correct Answer

(D) (I) \(\rightarrow\) (a), (II) \(\rightarrow\) (d), (III) \(\rightarrow\) (b), (IV) \(\rightarrow\) (c)

Step-by-step Solution

Detailed explanation

(d) \(\cos \alpha+\cos \beta=a \Rightarrow a=2 \cos \left(\frac{\alpha+\beta}{2}\right) \cos \left(\frac{\alpha-\beta}{2}\right)\) and \(\sin \alpha+\sin \beta=b \Rightarrow b=2 \sin \left(\frac{\alpha+\beta}{2}\right) \cos \left(\frac{\alpha-\beta}{2}\right)\)…