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Cosider the cubic equation : `x^3-(1+costheta+sintheta)x^2+(costhetasintheta+costheta+sintheta)x-sinthetacostheta=0` whose roots are `x_1,x_2,x_3`. The value of `(x_1)^2+(x_2)^2+(x_3)^2` equalsA. 1B. 2C. `2 cos theta`D. `sin theta (sin theta+ cos theta)` |
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Answer» Correct Answer - B `x^(3)-(1+cos theta + sin theta) x^(2) +(cos theta sin theta + cos theta + sin theta)x-sin theta cos theta=0` Given cubic function is `f(x)=(x-1)(x-cos theta) (x- sin theta)` Therefore, roots are `1, sin theta`, and `cos theta`. Hence, `x_(1)^(2)+x_(2)^(2)+x_(3)^(2)=1+sin^(2) theta+cos^(2) theta=2` |
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