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Choose the correct alternative:
sinθ × cosecθ =?
Concept: Angles of Elevation and Depression
If cosθ = `5/13`, then find sinθ.
Concept: Trigonometric Identities (Square Relations)
Verify that the points A(–2, 2), B(2, 2) and C(2, 7) are the vertices of a right-angled triangle.
Concept: Trigonometric Identities (Square Relations)
If sinθ = `8/17`, where θ is an acute angle, find the value of cos θ by using identities.
Concept: Angles of Elevation and Depression
Show that:
`sqrt((1-cos"A")/(1+cos"A"))=cos"ecA - cotA"`
Concept: Angles of Elevation and Depression
In ΔPQR, ∠P = 30°, ∠Q = 60°, ∠R = 90° and PQ = 12 cm, then find PR and QR.
Concept: Angles of Elevation and Depression
ΔAMT∼ΔAHE, construct Δ AMT such that MA = 6.3 cm, ∠MAT=120°, AT = 4.9 cm and `"MA"/"HA"=7/5`, then construct ΔAHE.
Concept: Angles of Elevation and Depression
If sec θ = `25/7`, find the value of tan θ.
Solution:
1 + tan2 θ = sec2 θ
∴ 1 + tan2 θ = `(25/7)^square`
∴ tan2 θ = `625/49 - square`
= `(625 - 49)/49`
= `square/49`
∴ tan θ = `square/7` ........(by taking square roots)
Concept: Trigonometric Identities (Square Relations)
If sin θ + sin2 θ = 1 show that: cos2 θ + cos4 θ = 1
Concept: Trigonometric Identities (Square Relations)
sin2θ + sin2(90 – θ) = ?
Concept: Trigonometric Identities (Square Relations)
`(1 - tan^2 45^circ)/(1 + tan^2 45^circ)` = ?
Concept: Trigonometric Identities (Square Relations)
If `tan θ = 9/40`, complete the activity to find the value of sec θ.
Activity:
sec2θ = 1 + `square` ...[Fundamental trigonometric identity]
sec2θ = 1 + `square^2`
sec2θ = 1 + `square`
sec θ = `square`
Concept: Trigonometric Identities (Square Relations)
Prove that `1/("cosec" θ - cot θ) = "cosec" θ + cot θ`.
Concept: Trigonometric Identities (Square Relations)
If `tan θ = 7/24`, then to find value of cos θ complete the activity given below.
Activity:
sec2θ = 1 + `square` ...[Fundamental tri. identity]
sec2θ = 1 + `square^2`
sec2θ = 1 + `square/576`
sec2θ = `square/576`
sec θ = `square`
cos θ = `square` ...`[cos theta = 1/sectheta]`
Concept: Trigonometric Identities (Square Relations)
Prove that `(sec A)/(tan A + cot A) = sin A`.
Concept: Trigonometric Identities (Square Relations)
Prove that `(cot A)/(1 - tan A) + (tan A)/(1 - cot A) = 1 + tan A + cot A = sec A . "cosec" A + 1`.
Concept: Trigonometric Identities (Square Relations)
The value of 2tan45° – 2sin30° is ______.
Concept: Trigonometric Table
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.
Concept: Trigonometric Identities (Square Relations)
If sinθ = `11/61`, then find the value of cosθ using the trigonometric identity.
Concept: Trigonometric Identities (Square Relations)
Show that: `tan "A"/(1 + tan^2 "A")^2 + cot "A"/(1 + cot^2 "A")^2 = sin"A" xx cos"A"`
Concept: Trigonometric Identities (Square Relations)
