Q27 of 268 Page 4

If 4sin2 θ =3 and 0o < θ <90o, find the value of 1 + cos θ.

4sin2 θ =3



But it is given 0o< θ <90o


So,



Let, P =k√3 and H =2k


In right angled ∆ABC, we have


B2 + P2 = H2


⇒ B2 + (k√3)2 = (2k)2


⇒ B2 + 3k2 = 4k2


⇒ B2 = 4k2 – 3k2


⇒ B2 = k2


⇒ B = ±k


⇒ B = k [taking positive square root since, side cannot be negative]



So,


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