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Question

The number of solutions for sin2x2+1=sinx+cosx in the interval (0,2π] is .

A
2
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B
Two
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C
2.0
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D
two.
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E
02
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Solution

Let's solve the trigonometric equation step by step using the factorization method.

Given: sin2x2+1=sinx+cosx
2sinxcosx2+1=sinx+cosx
sinxcosx+1=sinx+cosx

Step 1: Transform the equation into product of linear factors by bringing the RHS term to LHS and make the RHS as zero.
sinxcosx+1sinxcosx=0
sinxcosxsinx+1cosx=0

(taking sinx common from first two terms)
sinx(cosx1)+1cosx=0
(taking 1 common from last two terms)
sinx(cosx1)1(1+cosx)=0
sinx(cosx1)1(cosx1)=0

(taking (cosx1) common)
(cosx1)(sinx1)=0

Step 2: Equate each factor to zero.
Either cosx1=0 or sinx1=0

Step 3: Solve each equation individually.
For cosx1=0, i.e., cosx=1,x=2π in the interval (0,2π].

For sinx1=0, i.e., sinx=1,x=π2 in the interval (0,2π].

Step 4: Take union of all these solutions.
The complete solution is x={π2,2π} in the interval (0,2π].

Hence, the number of solutions is two in the given interval.

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