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Given : cos A=5/13 evaluate : cotA+1/...

Given : `cos A=5/13` evaluate :
`cotA+1/(cosA)`

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To solve the problem, we are given that \( \cos A = \frac{5}{13} \) and we need to evaluate \( \cot A + \frac{1}{\cos A} \). ### Step-by-Step Solution: 1. **Identify the Triangle**: We know that \( \cos A = \frac{\text{Base}}{\text{Hypotenuse}} \). Here, the base is 5 and the hypotenuse is 13. We can represent this in a right triangle where: - Base (adjacent side) = 5 - Hypotenuse = 13 2. **Find the Perpendicular Side**: To find the perpendicular side (opposite side), we can use the Pythagorean theorem: \[ \text{Hypotenuse}^2 = \text{Base}^2 + \text{Perpendicular}^2 \] Rearranging gives: \[ \text{Perpendicular}^2 = \text{Hypotenuse}^2 - \text{Base}^2 \] Plugging in the values: \[ \text{Perpendicular}^2 = 13^2 - 5^2 = 169 - 25 = 144 \] Taking the square root: \[ \text{Perpendicular} = \sqrt{144} = 12 \] 3. **Calculate \( \cot A \)**: The cotangent of angle A is given by: \[ \cot A = \frac{\text{Base}}{\text{Perpendicular}} = \frac{5}{12} \] 4. **Calculate \( \frac{1}{\cos A} \)**: We know \( \cos A = \frac{5}{13} \), so: \[ \frac{1}{\cos A} = \frac{1}{\frac{5}{13}} = \frac{13}{5} \] 5. **Combine the Results**: Now we can evaluate \( \cot A + \frac{1}{\cos A} \): \[ \cot A + \frac{1}{\cos A} = \frac{5}{12} + \frac{13}{5} \] 6. **Finding a Common Denominator**: The least common multiple (LCM) of 12 and 5 is 60. We convert each fraction: \[ \frac{5}{12} = \frac{5 \times 5}{12 \times 5} = \frac{25}{60} \] \[ \frac{13}{5} = \frac{13 \times 12}{5 \times 12} = \frac{156}{60} \] 7. **Add the Fractions**: Now we can add the two fractions: \[ \frac{25}{60} + \frac{156}{60} = \frac{25 + 156}{60} = \frac{181}{60} \] ### Final Answer: Thus, the value of \( \cot A + \frac{1}{\cos A} \) is \( \frac{181}{60} \).
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ICSE-TRIGONOMETRICAL RATIOS -EXERCISE 22(A)
  1. From the following figure , find the values of : cos^2A+sin^2A

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  2. Given : cos A=5/13 evaluate : (sinA-cotA)/(2 tanA)

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  3. Given : cos A=5/13 evaluate : cotA+1/(cosA)

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  4. Given : sec A= (29)/21 , evaluate : sin A-1/(tanA)

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  5. Given : tan A=4/3 , find : ("cosec"A)/(cot A- secA)

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  6. Given : 4 cot A = 3 , find : sinA

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  7. Given : 4 cot A = 3 , find : sec A

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  8. Given : 4 cot A = 3 , find : "cosec"^2A - cot^2A

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  9. Given : cos A = 0.6 , find all other trigono- metrical ratios for angl...

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  10. In a right - angled triangle , it is given that A is an acute angle an...

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  11. In a right - angled triangle , it is given that A is an acute angle an...

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  12. In a right - angled triangle , it is given that A is an acute angle an...

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  13. Given : sin theta = p/q , find cos theta + sin theta in terms of p an...

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  14. If cos A=1/2 and sin B =1/sqrt2 , find the value of : (tanA-tanB)/(1+t...

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  15. If 5 cot theta =12 , find the value of : "cosec" theta + sec theta

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  16. If tan x =1(1)/3 , find the value of : 4 sin^2x -3 cos^2x +2

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  17. If "cosec" theta = sqrt5 , find the value of : 2-sin^2theta - cos^2 ...

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  18. If "cosec" theta = sqrt5 , find the value of : 2+1/(sin^2theta)-(cos...

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  19. If sec A = sqrt2 , find the value of : (3 cos^2 A+5 tan^2A)/(4 tan^2...

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  20. If cot theta = 1 , find the value of : 5 tan^2 theta + 2 sin^2 theta...

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