Question

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Answer 1

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Answer 2

Răspuns:

tg15⁰=sin15⁰/cos15⁰

=sin(60⁰-45⁰)/cos(60⁰-45⁰)

=(sin60⁰cos45⁰-cos60⁰sin45⁰) / (cos60⁰cos45⁰+sin60⁰sin45⁰)

=(√3/2×√2/2-1/2×√2/2) / (1/2×√2/2+√3/2×√2/2)

=(√6/4-√2/4)/(√2/4+√6/4)

=(√6-√2)/4 / (√6+√2)/4

=(√6-√2) / (√6+√2)

raționalizăm

=(√6-√2)²/(6²-2²)

=(6-2√12+2)/(36-4)

=(10-2×2√3)/32

=(10-4√3)/32

=2(5-2√3)/32

=(5-2√3)/16

=5/16-√3/8