Shortcut Trick
By observing the equation sin θ + cos θ = √2, we identify that this condition is satisfied when θ = 45°.
Substituting θ = 45°: sin 45° + cos 45° = 1/√2 + 1/√2 = 2/√2 = √2.
Now, calculate the required value: cosec 45° + cot 45°.
cosec 45° = √2 and cot 45° = 1.
Result = √2 + 1.
∴ The correct answer is √2 + 1.
Alternate Method
Given: sin θ + cos θ = √2
Formula Used: (sin θ + cos θ)2 = sin2θ + cos2θ + 2 sin θ cos θ ; sin2θ + cos2θ = 1
⇒ Square both sides of the given equation: (sin θ + cos θ)2 = (√2)2
⇒ sin2θ + cos2θ + 2 sin θ cos θ = 2
⇒ 1 + 2 sin θ cos θ = 2
⇒ 2 sin θ cos θ = 1
⇒ sin 2θ = 1 ⇒ 2θ = 90° ⇒ θ = 45°
⇒ Now, cosec θ + cot θ = cosec 45° + cot 45°
⇒ cosec 45° = √2 and cot 45° = 1
⇒ Final value = √2 + 1. This corresponds to Option (4).
∴ The correct answer is √2 + 1.
Additional Information
Trigonometric Identity
The fundamental square identity is sin2θ + cos2θ = 1, which applies to all values of θ.
Reciprocal Relations
cosec θ = 1 / sin θ and cot θ = 1 / tan θ = cos θ / sin θ.
Values for 45°
For θ = 45°, sin θ = 1/√2, cos θ = 1/√2, tan θ = 1, and cot θ = 1.
Complementary Angles
If sin θ = cos α, then θ + α = 90°. In this problem, sin 45° = cos 45°.