If $$\cos \pi x = {x^2} - x + \frac{5}{4}{\text{,}}$$ then the value of x will be ?
A. 0
B. 1
C. -1
D. None of the above
Answer: Option D
Solution(By Examveda Team)
$$\eqalign{ & \cos \pi x = {x^2} - x + \frac{5}{4} \cr & = {x^2} - 2 \times x \times \frac{1}{2} + \frac{1}{4} - \frac{1}{4} + \frac{5}{4} \cr & = {\left( {x - \frac{1}{2}} \right)^2} + 1 > 1 \cr & = - 1 \leqslant \cos x \leqslant 1 \cr} $$∴ So, value of x is none of the above
Related Questions on Trigonometry
A. x = -y
B. x > y
C. x = y
D. x < y
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