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Without using trigonometric table, the v...

Without using trigonometric table, the value of
`cotthetatan(90^(@)-theta)-sec(90^(@)-theta)"cosec"theta+sin^(2)65^(@)+sin^(2)25^(@)+sqrt3tan5^(@)tan85^(@)`.

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To solve the expression \[ \text{cottheta} \cdot \tan(90^\circ - \theta) - \sec(90^\circ - \theta) \cdot \csc \theta + \sin^2 65^\circ + \sin^2 25^\circ + \sqrt{3} \tan 5^\circ \tan 85^\circ, \] we will break it down step by step. ### Step 1: Simplify the first part The first part of the expression is \[ \text{cottheta} \cdot \tan(90^\circ - \theta). \] Using the trigonometric identity, we know that \[ \tan(90^\circ - \theta) = \cot \theta. \] Thus, \[ \text{cottheta} \cdot \tan(90^\circ - \theta) = \cot \theta \cdot \cot \theta = \cot^2 \theta. \] ### Step 2: Simplify the second part Next, we simplify \[ -\sec(90^\circ - \theta) \cdot \csc \theta. \] Using the identity, we have \[ \sec(90^\circ - \theta) = \csc \theta. \] Thus, \[ -\sec(90^\circ - \theta) \cdot \csc \theta = -\csc \theta \cdot \csc \theta = -\csc^2 \theta. \] ### Step 3: Combine the first two parts Now we can combine the results from Step 1 and Step 2: \[ \cot^2 \theta - \csc^2 \theta. \] Using the identity \[ \csc^2 \theta - \cot^2 \theta = 1, \] we can rearrange this to: \[ \cot^2 \theta - \csc^2 \theta = -1. \] ### Step 4: Simplify the sine squares Next, we simplify \[ \sin^2 65^\circ + \sin^2 25^\circ. \] Using the identity \(\sin^2 A + \sin^2 B = 1 - \frac{1}{2}(\cos(2A) + \cos(2B))\), we can compute: \[ \sin^2 65^\circ + \sin^2 25^\circ = \sin^2 65^\circ + \cos^2 65^\circ = 1. \] ### Step 5: Simplify the tangent product Now we simplify \[ \sqrt{3} \tan 5^\circ \tan 85^\circ. \] Using the identity \(\tan(90^\circ - \theta) = \cot \theta\), we have \[ \tan 85^\circ = \cot 5^\circ. \] Thus, \[ \tan 5^\circ \tan 85^\circ = \tan 5^\circ \cdot \cot 5^\circ = 1. \] Therefore, \[ \sqrt{3} \tan 5^\circ \tan 85^\circ = \sqrt{3} \cdot 1 = \sqrt{3}. \] ### Step 6: Combine all parts Now we can combine all parts of the expression: \[ -1 + 1 + \sqrt{3} = \sqrt{3}. \] Thus, the final answer is \[ \sqrt{3}. \]
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CBSE COMPLEMENTARY MATERIAL-INTRODUCTION TO TRIGONOMETRY-SHORT ANSWER TYPE QUESTIONS
  1. (tanA+secA-1)/(tanA-secA+1)=(1+sinA)/(cosA)

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  2. Prove 1/(secx-tanx)-1/(cosx)=1/(cosx)-1/(secx+tanx)

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  3. (tantheta)/(1-cottheta)+(cottheta)/(1-tantheta)=1+tantheta+cottheta=se...

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  4. Prove that (sin theta + "cosec" theta)^(2)+(cos theta + sec theta)^(...

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  5. secA(1-sinA)(secA+tanA)=1

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  6. If tantheta+sintheta=m and tantheta-sintheta=n, then prove that: m^(2)...

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  7. If sectheta=x+(1)/(4x),prove that sectheta+tantheta=2xor(1)/(2x)*

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  8. If sintheta+sin^2theta=1 , prove that cos^2theta+cos^4theta=1

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  9. Without using trigonometric table, the value of cotthetatan(90^(@)-t...

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  10. Prove that : (cot(90^(@)-theta))/(tantheta)+("cosec"(90^(@)-theta)sint...

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  11. Without using trigonometric tables, evaluate each of the following: (...

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  12. If A, B, C are the angles of DeltaABC then prove that "cosec"^(2)((B+C...

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  13. Find the value of sec^(2)10^(@)-cot^(2)80^(@)+(sin15^(@)cos75^(@)+cos1...

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  14. Prove the following identities: (tantheta-cottheta)/(sinthetacostheta...

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  15. If sintheta+costheta=sqrt2costhetathen costheta-sintheta is equal to

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  16. Evaulate : 4-(sin30^(@)+tan45^(@)-"cosec"60^(@))/(sec30^(@)+cos60^(@)+...

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  17. Prove that : 1-(sinAsin(90^(@)-A))/(cot(90^(@)-A))=sin^(2)A

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  18. i) If acostheta+bsintheta=m and asintheta-bcostheta=n, then prove that...

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  19. If acostheta-bsintheta=c, then prove that: asintheta+bcostheta=+-sqr...

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  20. Without using trigonometric tables, evaluate each of the following: (...

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