Q22 of 242 Page 9

If sin α and cos α are the roots of the equation ax2 + bx + c = 0, then b2 =

Equation ax2 + bx + c = 0 has and as two roots


sin α + cos α =


sin α × cos α = c/a …eq(1)



…..eq (2)


But sin2 α + cos2 α = 1


∴ a2 (1 + 2 sinα.cos α) = b2


Putting sin α × cos α = c/a, we get,


⇒ b2 = a2 + 2ac.

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