A-4.a If a cos theta + b sin theta= 3 & a sin theta -b cos theta = 4 then value of a2 + b2 is
(1) 25
(2) 14
(3)

2 thoughts on “A-4.a If a cos theta + b sin theta= 3 & a sin theta -b cos theta = 4 then value of a2 + b2 is<br />(1) 25<br />(2) 14<br />(3)”

1. Answer:

   dbo-wpvt-kej

   j.oin .m.e.et

   don’t no answer sorry

   for inconvenience

   hope this helps

   mark as brainlest

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2. Step-by-step explanation:

   ⇒ acosθ+bsinθ=4 — ( 1 )

   ⇒ asinθ−bcosθ=3 — ( 2 )

   → Now, squaring and adding ( 1 ) and ( 2 )

   ∴ (acosθ+bsinθ)2+(asinθ−bcosθ)2=42+32

   ⇒ a2cos2θ+2ab.sinθcosθ+b2sin2θ+a2sin2θ−2ab.sinθcosθ+b2cos2θ=16+9

   ⇒ a2(sin2θ+cos2θ)+b2(sin2θ+cos2θ)=25

   ∴ a2+b2=25 [∵sin2x+cos2x=1]

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