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महाराष्ट्र राज्य शिक्षण मंडळएचएससी विज्ञान (सामान्य) इयत्ता १२ वी

Show that tan-1 12=13 tan-1 12

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प्रश्न

Show that `tan^-1  1/2 = 1/3  tan^-1  11/2`

बेरीज
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उत्तर

We have to show that

`tan^-1  1/2 = 1/3  tan^-1  11/2`

i.e. to show that `3 tan^-1  1/2 = tan^-1  11/2`

LHS = `3 tan^-1  1/2`

`= 2 tan^-1  1/2 + tan^-1  1/2`

`= tan^-1 [(2 xx 1/2)/(1 - (1/2)^2)] + tan^-1  1/2  .....[∵ 2tan^-1 "x" = tan^-1 ("2x"/"1 - x"^2)]`

`= tan^-1 [1/(3/4)] + tan^-1  1/2`

`= tan^-1  4/3 + tan^-1  1/2`

`= tan^-1 [(4/3 + 1/2)/(1 - 4/3 xx 1/2)]`

`= tan^-1 ((8 + 3)/(6 - 4))`

`= tan^-1 (11/2)` = RHS

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पाठ 3: Trigonometric Functions - Miscellaneous exercise 3 [पृष्ठ ११०]

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बालभारती Mathematics and Statistics 1 (Arts and Science) [English] Standard 12 Maharashtra State Board
पाठ 3 Trigonometric Functions
Miscellaneous exercise 3 | Q 32 | पृष्ठ ११०

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