Respuesta :
The requires value of x is -3pi/28.
What are trigonometric identities?
Trigonometric identities are the equalities that involve trigonometry functions and holds true for all the values of variables given in the equation.
It is given that-
sinxcos(pi/7) - sin(pi/7)cosx = -sqrt2/2
This can be written as-
sinxcos(pi/7) - sin(pi/7)cosx = -1/sqrt2
since sin(-pi/4) = -1/sqrt2
sinxcos(pi/7) - sin(pi/7)cosx = sin(-pi/4)
Using the trigonometry identity,
sinAcosB - cosAsinB = sin(A - B)
The given equation can be written as-
sin(x - pi/7) = sin(-pi/4)
⇒ x - pi/7 = -pi/4
⇒ x = -pi/4 + pi/7
⇒ x = -pi/4 + pi/7
⇒ x = -3pi/28
Hence,the required value of x is -3pi/28.
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