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sin4A – cos4A = 1 – 2cos2A. For proof of this complete the activity given below.
Activity:
L.H.S = `square`
= (sin2A + cos2A) `(square)`
= `1 (square)` .....`[sin^2"A" + square = 1]`
= `square` – cos2A .....[sin2A = 1 – cos2A]
= `square`
= R.H.S
Concept: undefined >> undefined
tan2θ – sin2θ = tan2θ × sin2θ. For proof of this complete the activity given below.
Activity:
L.H.S = `square`
= `square (1 - (sin^2theta)/(tan^2theta))`
= `tan^2theta (1 - square/((sin^2theta)/(cos^2theta)))`
= `tan^2theta (1 - (sin^2theta)/1 xx (cos^2theta)/square)`
= `tan^2theta (1 - square)`
= `tan^2theta xx square` .....[1 – cos2θ = sin2θ]
= R.H.S
Concept: undefined >> undefined
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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: undefined >> undefined
To prove cot θ + tan θ = cosec θ × sec θ, complete the activity given below.
Activity:
L.H.S = `square`
= `square/sintheta + sintheta/costheta`
= `(cos^2theta + sin^2theta)/square`
= `1/(sintheta*costheta)` ......`[cos^2theta + sin^2theta = square]`
= `1/sintheta xx 1/square`
= `square`
= R.H.S
Concept: undefined >> undefined
If 5 sec θ – 12 cosec θ = 0, then find values of sin θ, sec θ
Concept: undefined >> undefined
Prove that `(tan(90 - theta) + cot(90 - theta))/("cosec" theta)` = sec θ
Concept: undefined >> undefined
Prove that cot2θ – tan2θ = cosec2θ – sec2θ
Concept: undefined >> undefined
Prove that `sintheta/(sectheta+ 1) +sintheta/(sectheta - 1)` = 2 cot θ
Concept: undefined >> undefined
Prove that `sec"A"/(tan "A" + cot "A")` = sin A
Concept: undefined >> undefined
Prove that `(sintheta + "cosec" theta)/sin theta` = 2 + cot2θ
Concept: undefined >> undefined
Prove that `"cot A"/(1 - cot"A") + "tan A"/(1 - tan "A")` = – 1
Concept: undefined >> undefined
Prove that `sqrt((1 + cos "A")/(1 - cos"A"))` = cosec A + cot A
Concept: undefined >> undefined
Prove that sin4A – cos4A = 1 – 2cos2A
Concept: undefined >> undefined
Prove that sec2θ – cos2θ = tan2θ + sin2θ
Concept: undefined >> undefined
Prove that cosec θ – cot θ = `sin theta/(1 + cos theta)`
Concept: undefined >> undefined
Prove that `(1 + sec "A")/"sec A" = (sin^2"A")/(1 - cos"A")`
Concept: undefined >> undefined
Prove that `(1 + sin "B")/"cos B" + "cos B"/(1 + sin "B")` = 2 sec B
Concept: undefined >> undefined
Prove that
sin2A . tan A + cos2A . cot A + 2 sin A . cos A = tan A + cot A
Concept: undefined >> undefined
Prove that
sec2A – cosec2A = `(2sin^2"A" - 1)/(sin^2"A"*cos^2"A")`
Concept: undefined >> undefined
Prove that
`(cot "A" + "cosec A" - 1)/(cot"A" - "cosec A" + 1) = (1 + cos "A")/"sin A"`
Concept: undefined >> undefined
