Prove the Identity : \[ \frac{\sin^3 x+\cos^3 x}{\sin x+\cos x} + \frac{\sin^3 x-\cos^3 x}{\sin x-\cos x} =2 \] Solution: \[ \frac{(\sin x+\cos x)(\sin^2 x-\sin x\cos x+\cos^2 x)} {\sin x+\cos x} \] \[ + \frac{(\sin x-\cos x)(\sin^2 x+\sin x\cos x+\cos^2 x)} {\sin x-\cos x} \] \[ = \sin^2 x-\sin x\cos x+\cos^2 x \] \[ + \sin^2
Prove the Identity : \[ \frac{\tan x}{1-\cot x}+\frac{\cot x}{1-\tan x} = \sec x\cosec x+1 \] Solution: \[ \frac{\tan x}{1-\cot x}+\frac{\cot x}{1-\tan x} \] \[ = \frac{\frac{\sin x}{\cos x}} {1-\frac{\cos x}{\sin x}} + \frac{\frac{\cos x}{\sin x}} {1-\frac{\sin x}{\cos x}} \] \[ = \frac{\sin^2 x}{\cos x(\sin x-\cos x)} + \frac{\cos^2 x}{\sin x(\cos x-\sin x)} \] \[ =
Prove the Identity : \[ \frac{1-\sin x\cos x}{\cos x(\sec x-\cosec x)} \cdot \frac{\sin^2 x-\cos^2 x}{\sin^3 x+\cos^3 x} = \sin x \] Solution: \[ \frac{1-\sin x\cos x}{\cos x\left(\frac{1}{\cos x}-\frac{1}{\sin x}\right)} \cdot \frac{\sin^2 x-\cos^2 x}{\sin^3 x+\cos^3 x} \] \[ = \frac{1-\sin x\cos x}{\frac{\sin x-\cos x}{\sin x}} \cdot \frac{(\sin x-\cos x)(\sin x+\cos x)} {(\sin x+\cos x)(\sin^2 x-\sin x\cos
Prove the Identity : \( \cosec x(\sec x-1)-\cot x(1-\cos x)=\tan x-\sin x \) Solution: \[ \cosec x(\sec x-1)-\cot x(1-\cos x) \] \[ =\frac{1}{\sin x}\left(\frac{1}{\cos x}-1\right) -\frac{\cos x}{\sin x}(1-\cos x) \] \[ =\frac{1-\cos x}{\sin x\cos x} -\frac{\cos x(1-\cos x)}{\sin x} \] \[ =\frac{1-\cos x-\cos^2 x(1-\cos x)}{\sin x\cos x} \] \[ =\frac{(1-\cos x)(1-\cos^2 x)}{\sin x\cos x} \]
Prove the following identity : cosec x (sec x – 1) – cot x(1 – cos x) = tan x – sin x Read More »
Prove the Identity : \( (\cosec x-\sin x)(\sec x-\cos x)(\tan x+\cot x)=1 \) Solution: \[ (\cosec x-\sin x)(\sec x-\cos x)(\tan x+\cot x) \] \[ =\left(\frac{1}{\sin x}-\sin x\right) \left(\frac{1}{\cos x}-\cos x\right) \left(\frac{\sin x}{\cos x}+\frac{\cos x}{\sin x}\right) \] \[ =\frac{1-\sin^2 x}{\sin x}\cdot \frac{1-\cos^2 x}{\cos x}\cdot \frac{\sin^2 x+\cos^2 x}{\sin x\cos x} \] \[ =\frac{\cos^2 x}{\sin x}\cdot \frac{\sin^2 x}{\cos
Prove the following identity : (cosec x – sin x) (sec x – cos x) (tan x + cot x) = 1 Read More »
Prove the Identity : \( \sin^6 x + \cos^6 x = 1 – 3\sin^2 x \cos^2 x \) Solution: \[ \sin^6 x + \cos^6 x \] \[ = (\sin^2 x)^3 + (\cos^2 x)^3 \] \[ = (\sin^2 x+\cos^2 x)(\sin^4 x-\sin^2 x\cos^2 x+\cos^4 x) \] \[ = \sin^4 x-\sin^2 x\cos^2 x+\cos^4 x \] \[ = (\sin^2
Prove the following identity : sin^6 x + cos^6 x = 1 – 3sin^2 x cos^2 x Read More »
Prove the Identity : \( \sec^4 x – \sec^2 x = \tan^4 x + \tan^2 x \) Solution: \[ \sec^4 x – \sec^2 x \] \[ = \sec^2 x(\sec^2 x-1) \] \[ = \sec^2 x \tan^2 x \] \[ = (1+\tan^2 x)\tan^2 x \] \[ = \tan^2 x+\tan^4 x \] \[ = \tan^4 x+\tan^2 x
Prove the following identity : sec^4 x – sec^2 x = tan^4 x + tan^2 x Read More »
The Radius of the Circle Whose Arc of Length \(15\pi\) cm Makes an Angle of \(\frac{3\pi}{4}\) Radian at the Centre Question: The radius of the circle whose arc of length \(15\pi\) cm makes an angle of \(\frac{3\pi}{4}\) radian at the centre is (a) \(10\) cm (b) \(20\) cm (c) \(11 \frac{1}{4}\) cm (d) \(22 \frac{1}{2}\)
A Circular Wire of Radius 7 cm is Cut and Bent Again into an Arc of a Circle of Radius 12 cm Question: A circular wire of radius \(7\) cm is cut and bent again into an arc of a circle of radius \(12\) cm. The angle subtended by the arc at the center is
If OP Makes 4 Revolutions in One Second, the Angular Velocity in Radians per Second is Question: If OP makes \(4\) revolutions in one second, the angular velocity in radians per second is (a) \(\pi\) (b) \(2\pi\) (c) \(4\pi\) (d) \(8\pi\) Solution We know that: \[ 1 \text{ revolution} = 2\pi \text{ radians} \] Given