MCQ
If the system of equation
$2 x+\lambda y+3 z=5$
$3 x+2 y-z=7$
$4 x+5 y+\mu z=9$
has infinitely many solutions, then $\left(\lambda^{2}+\mu^{2}\right)$ is equal to :
  • A
    22
  • B
    18
  • C
    26
  • D
    30

Answer

C. 26
$\Delta=0 \Rightarrow\left|\begin{array}{ccc}2 & \lambda & 3 \\ 3 & 2 & -1 \\ 4 & 5 & \mu\end{array}\right|=0$
$\Rightarrow 2(2 \mu+5)+\lambda(-4-3 \mu)+3(7)=0$
$\Rightarrow 4 \mu-3 \lambda \mu-4 \lambda+31=0 \ldots .$. (1)
$\Delta_{3}=0 \Rightarrow\left|\begin{array}{lll}2 & \lambda & 5 \\ 3 & 2 & 7 \\ 4 & 5 & 9\end{array}\right|=0$
$\Rightarrow 2(-17)+\lambda(1)+5(7)=0$
$\Rightarrow \lambda=-1$
from equation (1)
$4 \mu+3 \mu+4+31=0 \Rightarrow \mu=-5$
$\therefore \lambda^{2}+\mu^{2}=26$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

$\int_{}^{} {{e^{x/2}}\sin \left( {\frac{x}{2} + \frac{\pi }{4}} \right)\;dx = } $
Which of the following statements is incorrect for the function $g(\alpha)$ for $\alpha \in R$ such that

$g(\alpha)=\int_{\frac{\pi}{6}}^{\frac{\pi}{3}} \frac{\sin ^{\alpha} x}{\cos ^{\alpha} x+\sin ^{\alpha} x} d x$

Let $y = y _1( x )$ and $y = y _2( x )$ be the solution curves of the differential equation $\frac{d y}{d x}=y+7$ with initial conditions $y_1(0)=0, y_2(0)=1$ respectively. Then the curves $y=y_1(x)$ and $y=y_2(x)$ intersect at
The value of $\left(\frac{1+\sin \frac{2 \pi}{9}+i \cos \frac{2 \pi}{9}}{1+\sin \frac{2 \pi}{9}-i \cos \frac{2 \pi}{9}}\right)^3$ is
One of the limit point of the coaxial system of circles containing ${x^2} + {y^2} - 6x - 6y + 4 = 0$, ${x^2} + {y^2} - 2x$ $ - 4y + 3 = 0$ is
Equation of curve passing through $(3, 9)$ which satisfies the differential equation $\frac{{dy}}{{dx}} = x + \frac{1}{{{x^2}}}$, is
Let ${z_1}$ and ${z_2}$ be $n^{th}$ roots of unity which are ends of a line segment that subtend a right angle at the origin. Then $n$ must be of the form
Let $\vec{p}=2 \hat{i}+\hat{j}+3 \hat{k}$ and $\vec{q}=\hat{i}-\hat{j}+\hat{k}$. If for some real numbers $\alpha, \beta$ and $\gamma$, we have $15 \hat{i}+10 \hat{j}+6 \hat{k}=\alpha(2 \vec{p}+\vec{q})+\beta(\vec{p}-2 \vec{q})+\gamma(\vec{p} \times \vec{q})$, then the value of $\gamma$ is$...........$
If ${x^2} - hx - 21 = 0,{x^2} - 3hx + 35 = 0$$(h > 0)$ has a common root, then the value of $h$ is equal to
If $a,\;b,\;c$ are in A.P., then the straight line $ax + by + c = 0$ will always pass through the point