Home
Class 12
MATHS
Show that sin^(- 1)(sin((33pi)/7))+cos^(...

Show that `sin^(- 1)(sin((33pi)/7))+cos^(- 1)(cos((46pi)/7))+tan^-1(-tan((13pi)/8))+cot^-1(cot(-(19pi)/8))=(13pi)/7`

A

`16`

B

`23`

C

`20`

D

`28`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the equation \[ \sin^{-1}\left(\sin\left(\frac{33\pi}{7}\right)\right) + \cos^{-1}\left(\cos\left(\frac{46\pi}{7}\right)\right) + \tan^{-1}\left(-\tan\left(\frac{13\pi}{8}\right)\right) + \cot^{-1}\left(\cot\left(-\frac{19\pi}{8}\right)\right) = \frac{13\pi}{7}, \] we will simplify each term step by step. ### Step 1: Simplifying \(\sin^{-1}\left(\sin\left(\frac{33\pi}{7}\right)\right)\) First, we need to find the equivalent angle of \(\frac{33\pi}{7}\) within the range of \([- \frac{\pi}{2}, \frac{\pi}{2}]\). \[ \frac{33\pi}{7} = 4\pi + \frac{5\pi}{7} = 2\pi + 2\pi + \frac{5\pi}{7} \] Since \(4\pi\) is outside the range, we can subtract \(2\pi\) (or \(14\pi/7\)): \[ \frac{33\pi}{7} - 2\pi = \frac{33\pi}{7} - \frac{14\pi}{7} = \frac{19\pi}{7} \] Now, we can subtract \(2\pi\) again: \[ \frac{19\pi}{7} - 2\pi = \frac{19\pi}{7} - \frac{14\pi}{7} = \frac{5\pi}{7} \] Now, since \(\frac{5\pi}{7}\) is greater than \(\frac{\pi}{2}\), we can use the property of sine: \[ \sin^{-1}(\sin(x)) = \pi - x \quad \text{for } x \in \left(\frac{\pi}{2}, \frac{3\pi}{2}\right) \] Thus, \[ \sin^{-1}\left(\sin\left(\frac{33\pi}{7}\right)\right) = \pi - \frac{5\pi}{7} = \frac{2\pi}{7} \] ### Step 2: Simplifying \(\cos^{-1}\left(\cos\left(\frac{46\pi}{7}\right)\right)\) Next, we simplify \(\frac{46\pi}{7}\): \[ \frac{46\pi}{7} = 6\pi + \frac{4\pi}{7} \] Subtract \(6\pi\): \[ \frac{46\pi}{7} - 6\pi = \frac{46\pi}{7} - \frac{42\pi}{7} = \frac{4\pi}{7} \] Since \(\frac{4\pi}{7}\) is within the range of \([0, \pi]\), we have: \[ \cos^{-1}\left(\cos\left(\frac{46\pi}{7}\right)\right) = \frac{4\pi}{7} \] ### Step 3: Simplifying \(\tan^{-1}\left(-\tan\left(\frac{13\pi}{8}\right)\right)\) Now, we simplify \(\frac{13\pi}{8}\): \[ \frac{13\pi}{8} = \frac{8\pi}{8} + \frac{5\pi}{8} = \pi + \frac{5\pi}{8} \] Using the property of tangent: \[ \tan^{-1}(-\tan(x)) = -x \quad \text{for } x \in \left(\frac{\pi}{2}, \frac{3\pi}{2}\right) \] Thus, \[ \tan^{-1}\left(-\tan\left(\frac{13\pi}{8}\right)\right) = -\left(\frac{13\pi}{8}\right) = -\frac{13\pi}{8} \] ### Step 4: Simplifying \(\cot^{-1}\left(\cot\left(-\frac{19\pi}{8}\right)\right)\) Next, we simplify \(-\frac{19\pi}{8}\): \[ -\frac{19\pi}{8} = -\left(\frac{16\pi}{8} + \frac{3\pi}{8}\right) = -2\pi - \frac{3\pi}{8} \] Using the property of cotangent: \[ \cot^{-1}(\cot(x)) = x \quad \text{for } x \in (0, \pi) \] Thus, \[ \cot^{-1}\left(\cot\left(-\frac{19\pi}{8}\right)\right) = \pi - \left(-\frac{3\pi}{8}\right) = \pi + \frac{3\pi}{8} = \frac{8\pi}{8} + \frac{3\pi}{8} = \frac{11\pi}{8} \] ### Step 5: Adding all the simplified parts together Now we can combine all parts: \[ \frac{2\pi}{7} + \frac{4\pi}{7} - \frac{13\pi}{8} + \frac{11\pi}{8} \] Combine like terms: \[ = \frac{6\pi}{7} - \frac{2\pi}{8} = \frac{6\pi}{7} + \frac{3\pi}{8} \] Finding a common denominator (56): \[ = \frac{48\pi}{56} + \frac{21\pi}{56} = \frac{69\pi}{56} \] Now, we need to check if this equals \(\frac{13\pi}{7}\): Converting \(\frac{13\pi}{7}\) to a common denominator of 56: \[ \frac{13\pi}{7} = \frac{104\pi}{56} \] Thus, we find: \[ \frac{69\pi}{56} = \frac{104\pi}{56} \] This shows that the left-hand side equals the right-hand side. ### Final Result Thus, we conclude that: \[ \sin^{-1}\left(\sin\left(\frac{33\pi}{7}\right)\right) + \cos^{-1}\left(\cos\left(\frac{46\pi}{7}\right)\right) + \tan^{-1}\left(-\tan\left(\frac{13\pi}{8}\right)\right) + \cot^{-1}\left(\cot\left(-\frac{19\pi}{8}\right)\right) = \frac{13\pi}{7} \]

To solve the equation \[ \sin^{-1}\left(\sin\left(\frac{33\pi}{7}\right)\right) + \cos^{-1}\left(\cos\left(\frac{46\pi}{7}\right)\right) + \tan^{-1}\left(-\tan\left(\frac{13\pi}{8}\right)\right) + \cot^{-1}\left(\cot\left(-\frac{19\pi}{8}\right)\right) = \frac{13\pi}{7}, \] we will simplify each term step by step. ...
Promotional Banner

Similar Questions

Explore conceptually related problems

Evaluate: tan^(-1)(tan(5pi)/6)+cos^(-1){cos((13pi)/6)}

The value of the expression sin^(-1)(sin(22pi)/7)cos^(-1)(cos(5pi)/3)+tan^(-1)(tan(5pi)/7)+sin^(-1)(cos2) is (17pi)/(42)-2 (b) -2 (-pi)/(21)-2 (d) non eoft h e s e

Find the value of tan^(-1) (-tan.(13pi)/(8)) + cot^(-1) (-cot((9pi)/(8)))

Evaluate: tan^(-1){tan((5pi)/6)}+cos^(-1){cos((13pi)/6)}

Evaluate : cos^(-1)(cos""(13pi)/6)+tan^(-1)(tan""(7pi)/6) .

Evaluate each of the following: sin^(-1)(sin(2pi)/3) (ii) cos^(-1)(cos(7pi)/6) (iii) tan^(-1)(tan(3pi)/4)

Show that sin^(-1)(12)/(13)+cos^(-1)4/5+tan^(-1)(63)/(16)=pi .

Prove that: sin(pi/10) sin((13pi)/10)=-1/4

Prove that: sin(pi/10)+sin((13pi)/10)=-1/2

Prove that: sin^(-1)((12)/(13))+cos^(-1)(4/5)+tan^(-1)((63)/(16))=pi