Consider the following two statements :- Statement p : The value of $sin120^\circ$ can be derived by taking $\theta = 240^\circ$ in the equation $2sin \frac{\theta}{2} = \sqrt{1+sin \theta} - \sqrt{1-sin \theta}$ Statement q : The angles A, B, C and D of any quadrilateral ABCD satisfy the equation $cos \left( \frac{1}{2}(A+C) \right) + cos \left( \frac{1}{2}(B+D) \right) = 0$ Then the truth values of p and q are respectively :-
We need to verify if $2\sin \frac{\theta}{2} = \sqrt{1+\sin \theta} - \sqrt{1-\sin \theta}$ holds true for $\theta = 240^\circ$.
Let $\theta = 240^\circ$, then $\frac{\theta}{2} = 120^\circ$. The left side (LHS) is $2\sin(120^\circ) = 2 \times \frac{\sqrt{3}}{2} = \sqrt{3}$.
For the right side (RHS), we use the identities: $1 + \sin \theta = (\sin(\theta/2) + \cos(\theta/2))^2$ $1 - \sin \theta = (\cos(\theta/2) - \sin(\theta/2))^2$ So, $\sqrt{1+\sin \theta} = |\sin(\theta/2) + \cos(\theta/2)|$ And $\sqrt{1-\sin \theta} = |\cos(\theta/2) - \sin(\theta/2)|$
Substitute $\theta/2 = 120^\circ$: $\sin(120^\circ) = \frac{\sqrt{3}}{2}$ $\cos(120^\circ) = -\frac{1}{2}$
Calculate the terms inside the absolute values: $\sin(120^\circ) + \cos(120^\circ) = \frac{\sqrt{3}}{2} - \frac{1}{2} = \frac{\sqrt{3}-1}{2}$ (Positive) $\cos(120^\circ) - \sin(120^\circ) = -\frac{1}{2} - \frac{\sqrt{3}}{2} = -\frac{1+\sqrt{3}}{2}$ (Negative)
Evaluate the absolute values: $|\sin(120^\circ) + \cos(120^\circ)| = \frac{\sqrt{3}-1}{2}$ $|\cos(120^\circ) - \sin(120^\circ)| = |-\frac{1+\sqrt{3}}{2}| = \frac{1+\sqrt{3}}{2}$
RHS = $|\sin(120^\circ) + \cos(120^\circ)| - |\cos(120^\circ) - \sin(120^\circ)| = \frac{\sqrt{3}-1}{2} - \frac{1+\sqrt{3}}{2} = \frac{\sqrt{3}-1 - 1 - \sqrt{3}}{2} = \frac{-2}{2} = -1$.
Since LHS ($\sqrt{3}$) is not equal to RHS (-1), Statement p is False.
Let A, B, C, D be the angles of a quadrilateral. The sum of the angles is $A+B+C+D = 360^\circ$. We need to check if $\cos \left( \frac{1}{2}(A+C) \right) + \cos \left( \frac{1}{2}(B+D) \right) = 0$.
From the sum of angles, $A+C = 360^\circ - (B+D)$. Dividing by 2, we get $\frac{1}{2}(A+C) = \frac{1}{2}(360^\circ - (B+D)) = 180^\circ - \frac{1}{2}(B+D)$.
Substitute this into the equation: $\cos \left( 180^\circ - \frac{1}{2}(B+D) \right) + \cos \left( \frac{1}{2}(B+D) \right)$
Using the trigonometric identity $\cos(180^\circ - x) = -\cos x$, where $x = \frac{1}{2}(B+D)$: $-\cos \left( \frac{1}{2}(B+D) \right) + \cos \left( \frac{1}{2}(B+D) \right) = 0$.
The equation $0 = 0$ is true. Therefore, Statement q is True.
Statement p is False (F) and Statement q is True (T). The truth values are (F, T).
A line passing through the point $P(\sqrt{5}, \sqrt{5})$ intersects the ellipse $\frac{x^2}{36} + \frac{y^2}{25} = 1$ at A and B such that $(PA).(PB)$ is maximum. Then $5(PA^2 + PB^2)$ is equal to :
The number of solutions of the equation $\cos 2\theta \cos \frac{\theta}{2} + \cos \frac{5\theta}{2} = 2\cos^3 \frac{5\theta}{2}$ in $\left[-\frac{\pi}{2}, \frac{\pi}{2}\right]$is :
The number of solutions of $sin3x = cos2x$, in the interval $\left[ \frac{\pi}{2}, \pi \right]$ is :-
If $y=\cos\left(\frac{\pi}{3}+\cos^{-1}\frac{x}{2}\right)$, then $(x-y)^2+3y^2$ is equal to ____________.
Let A(4, -2), B(1, 1) and C(9, -3) be the vertices of a triangle ABC. Then the maximum area of the parallelogram AFDE, formed with vertices D, E and F on the sides BC, CA and AB of the triangle ABC respectively, is ______________.
A line passing through the point $P(\sqrt{5}, \sqrt{5})$ intersects the ellipse $\frac{x^2}{36} + \frac{y^2}{25} = 1$ at A and B such that $(PA).(PB)$ is maximum. Then $5(PA^2 + PB^2)$ is equal to :