The value of 2sinθ can be a+(1/a), where a is a positive number and a≠1. Write ‘True’ or ‘False’ and justify your answer
Solution:
Given, a is positive number and a ≠ 1
We have to determine if 2sinθ can be a + (1/a)
Arithmetic mean of a and 1/a = a + (1/a) / 2
Geometric mean of a and 1/a = √a × (1/a) = 1
So, arithmetic mean > geometric mean
i.e., [a + (1/a)]/2 > 1
[a + (1/a)] > 2
Now, 2sinθ > 2
sinθ > 1
Therefore, 2sinθ cannot be a + (1/a)
✦ Try This: If 5sin A = 3, find cos A
Given, 5sin A = 3
We have to find cos A
sin A = 3/5
We know that sin A = opposite/hypotenuse
By using pythagorean theorem,
(hypotenuse)² = (opposite)² + (adjacent)²
(5)² = (adjacent)² + (3)²
25 = (adjacent)² + 9
(adjacent)² = 25 - 9
(adjacent)² = 16
Taking square root,
adjacent = 4
We know that cos A = adjacent/hypotenuse
cos A = 4/5
Therefore, the value of cos A is 4/5.
☛ Also Check: NCERT Solutions for Class 10 Maths Chapter 8
NCERT Exemplar Class 10 Maths Exercise 8.2 Problem 9
The value of 2sinθ can be a+(1/a), where a is a positive number and a≠1. Write ‘True’ or ‘False’ and justify your answer
Summary:
The statement “The value of 2sinθ can be a+(1/a), where a is a positive number and a≠1” is false
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