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If sin θ + cos θ = 7/5, then sinθ cosθ is?
  • a)
    11/25
  • b)
    12/25
  • c)
    13/25
  • d)
    14/25
Correct answer is option 'B'. Can you explain this answer?
Verified Answer
If sin θ + cos θ = 7/5, then sinθ cosθ is?a)11...
Concept:
sin2 x + cos2 x = 1
Calculation:
Given: sin θ + cos θ = 7/5 
By, squaring both sides of the above equation we get,
⇒ (sin θ + cos θ)2 = 49/25
⇒ sin2 θ + cos2 θ + 2sin θ.cos θ = 49/25
As we know that, sin2 x + cos2 x = 1
⇒ 1 + 2sin θcos θ = 49/25
⇒ 2sin θcos θ = 24/25
∴ sin θcos θ = 12/25
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Most Upvoted Answer
If sin θ + cos θ = 7/5, then sinθ cosθ is?a)11...
Given Equation
Given that:
- sin(θ) + cos(θ) = 7/5
Finding sin²(θ) + cos²(θ)
We know from trigonometric identities that:
- sin²(θ) + cos²(θ) = 1
Squaring the Given Equation
Now, if we square both sides of the equation:
- (sin(θ) + cos(θ))² = (7/5)²
This expands to:
- sin²(θ) + cos²(θ) + 2sin(θ)cos(θ) = 49/25
Substituting the identity:
- 1 + 2sin(θ)cos(θ) = 49/25
Solving for sin(θ)cos(θ)
Now, let's isolate 2sin(θ)cos(θ):
- 2sin(θ)cos(θ) = 49/25 - 1
Convert 1 to a fraction:
- 1 = 25/25
Now, subtract:
- 2sin(θ)cos(θ) = 49/25 - 25/25 = 24/25
Calculating sin(θ)cos(θ)
To find sin(θ)cos(θ):
- sin(θ)cos(θ) = (24/25) / 2 = 12/25
Conclusion
Thus, the value of sin(θ)cos(θ) is:
- 12/25, matching option B.
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Community Answer
If sin θ + cos θ = 7/5, then sinθ cosθ is?a)11...
Concept:
sin2 x + cos2 x = 1
Calculation:
Given: sin θ + cos θ = 7/5 
By, squaring both sides of the above equation we get,
⇒ (sin θ + cos θ)2 = 49/25
⇒ sin2 θ + cos2 θ + 2sin θ.cos θ = 49/25
As we know that, sin2 x + cos2 x = 1
⇒ 1 + 2sin θcos θ = 49/25
⇒ 2sin θcos θ = 24/25
∴ sin θcos θ = 12/25
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If sin θ + cos θ = 7/5, then sinθ cosθ is?a)11/25b)12/25c)13/25d)14/25Correct answer is option 'B'. Can you explain this answer?
Question Description
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