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प्रश्न
cos 45° = ?
विकल्प
sin 45°
sec 45°
cot 45°
tan 45°
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उत्तर
sin 45°
Explanation:
`cos 45^circ = 1/sqrt2`, `sin 45^circ = 1/sqrt(2)`
∴ cos 45° = sin 45°
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संबंधित प्रश्न
(1 + tan θ + sec θ) (1 + cot θ − cosec θ) = ______.
Prove the following trigonometric identities.
`1 + cot^2 theta/(1 + cosec theta) = cosec theta`
if `x/a cos theta + y/b sin theta = 1` and `x/a sin theta - y/b cos theta = 1` prove that `x^2/a^2 + y^2/b^2 = 2`
Prove the following identities:
(sin A + cosec A)2 + (cos A + sec A)2 = 7 + tan2 A + cot2 A
Prove the following identities:
`sqrt((1 - cosA)/(1 + cosA)) = sinA/(1 + cosA)`
Prove the following identities:
`cot^2A((secA - 1)/(1 + sinA)) + sec^2A((sinA - 1)/(1 + secA)) = 0`
Write the value of `(1 + tan^2 theta ) cos^2 theta`.
From the figure find the value of sinθ.
If cosec θ − cot θ = α, write the value of cosec θ + cot α.
If sec2 θ (1 + sin θ) (1 − sin θ) = k, then find the value of k.
Prove the following identity :
`(1 - sin^2θ)sec^2θ = 1`
Prove the following identity :
`(secA - 1)/(secA + 1) = (1 - cosA)/(1 + cosA)`
Prove the following identity :
`(cosecA)/(cosecA - 1) + (cosecA)/(cosecA + 1) = 2sec^2A`
Prove the following identity :
`(1 + cotA + tanA)(sinA - cosA) = secA/(cosec^2A) - (cosecA)/sec^2A`
`(sin A)/(1 + cos A) + (1 + cos A)/(sin A)` = 2 cosec A
Prove that `(cot "A" + "cosec A" - 1)/(cot "A" - "cosec A" + 1) = (1 + cos "A")/sin "A"`
Prove that sin6A + cos6A = 1 – 3sin2A . cos2A.
Given that sinθ + 2cosθ = 1, then prove that 2sinθ – cosθ = 2.
Complete the following activity to prove:
cotθ + tanθ = cosecθ × secθ
Activity: L.H.S. = cotθ + tanθ
= `cosθ/sinθ + square/cosθ`
= `(square + sin^2theta)/(sinθ xx cosθ)`
= `1/(sinθ xx cosθ)` ....... ∵ `square`
= `1/sinθ xx 1/cosθ`
= `square xx secθ`
∴ L.H.S. = R.H.S.
(sec2 θ – 1) (cosec2 θ – 1) is equal to ______.
