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Question
If sin θ + cos θ = `sqrt(3)`, then prove that tan θ + cot θ = 1.
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Solution
sin θ + cos θ = `sqrt(3)`
Squaring on both sides:
(sin θ + cos θ)2 = `(sqrt(3))^2`
sin2 θ + cos2 θ + 2 sin θ cos θ = 3
1 + 2 sin θ cos θ = 3
2 sin θ cos θ = 3 – 1
2 sin θ cos θ = 2
∴ sin θ cos θ = 1
L.H.S = tan θ + cot θ
= `sin theta/cos theta + cos theta/sin theta`
= `(sin^2 theta + cos^2 theta)/(sin theta cos theta)`
= `1/(sin theta cos theta)`
= `1/1` ...(sin θ cos θ = 1)
= 1 = R.H.S.
⇒ tan θ + cot θ = 1
L.H.S = R.H.S
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Prove the following identities.
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If sec θ = `25/7`, find the value of tan θ.
Solution:
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∴ 1 + tan2 θ = `(25/7)^square`
∴ tan2 θ = `625/49 - square`
= `(625 - 49)/49`
= `square/49`
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