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Description: The square root of two to the power of the logarithm of nine to base two is three. ( sqrt2 ) and ( 2 logb 9 ) are irrational numbers (see sqrt2irr0 resp. 2logb9irr ), satisfying the statement in 2irrexpqALT . (Contributed by AV, 29-Dec-2022)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | sqrt2cxp2logb9e3 | ⊢ ( ( √ ‘ 2 ) ↑𝑐 ( 2 logb 9 ) ) = 3 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 2cn | ⊢ 2 ∈ ℂ | |
| 2 | cxpsqrt | ⊢ ( 2 ∈ ℂ → ( 2 ↑𝑐 ( 1 / 2 ) ) = ( √ ‘ 2 ) ) | |
| 3 | 1 2 | ax-mp | ⊢ ( 2 ↑𝑐 ( 1 / 2 ) ) = ( √ ‘ 2 ) |
| 4 | 3 | eqcomi | ⊢ ( √ ‘ 2 ) = ( 2 ↑𝑐 ( 1 / 2 ) ) |
| 5 | 4 | oveq1i | ⊢ ( ( √ ‘ 2 ) ↑𝑐 ( 2 logb 9 ) ) = ( ( 2 ↑𝑐 ( 1 / 2 ) ) ↑𝑐 ( 2 logb 9 ) ) |
| 6 | 2rp | ⊢ 2 ∈ ℝ+ | |
| 7 | halfre | ⊢ ( 1 / 2 ) ∈ ℝ | |
| 8 | 2z | ⊢ 2 ∈ ℤ | |
| 9 | uzid | ⊢ ( 2 ∈ ℤ → 2 ∈ ( ℤ≥ ‘ 2 ) ) | |
| 10 | 8 9 | ax-mp | ⊢ 2 ∈ ( ℤ≥ ‘ 2 ) |
| 11 | 9nn | ⊢ 9 ∈ ℕ | |
| 12 | nnrp | ⊢ ( 9 ∈ ℕ → 9 ∈ ℝ+ ) | |
| 13 | 11 12 | ax-mp | ⊢ 9 ∈ ℝ+ |
| 14 | relogbzcl | ⊢ ( ( 2 ∈ ( ℤ≥ ‘ 2 ) ∧ 9 ∈ ℝ+ ) → ( 2 logb 9 ) ∈ ℝ ) | |
| 15 | 10 13 14 | mp2an | ⊢ ( 2 logb 9 ) ∈ ℝ |
| 16 | cxpcom | ⊢ ( ( 2 ∈ ℝ+ ∧ ( 1 / 2 ) ∈ ℝ ∧ ( 2 logb 9 ) ∈ ℝ ) → ( ( 2 ↑𝑐 ( 1 / 2 ) ) ↑𝑐 ( 2 logb 9 ) ) = ( ( 2 ↑𝑐 ( 2 logb 9 ) ) ↑𝑐 ( 1 / 2 ) ) ) | |
| 17 | 6 7 15 16 | mp3an | ⊢ ( ( 2 ↑𝑐 ( 1 / 2 ) ) ↑𝑐 ( 2 logb 9 ) ) = ( ( 2 ↑𝑐 ( 2 logb 9 ) ) ↑𝑐 ( 1 / 2 ) ) |
| 18 | 15 | recni | ⊢ ( 2 logb 9 ) ∈ ℂ |
| 19 | cxpcl | ⊢ ( ( 2 ∈ ℂ ∧ ( 2 logb 9 ) ∈ ℂ ) → ( 2 ↑𝑐 ( 2 logb 9 ) ) ∈ ℂ ) | |
| 20 | 1 18 19 | mp2an | ⊢ ( 2 ↑𝑐 ( 2 logb 9 ) ) ∈ ℂ |
| 21 | cxpsqrt | ⊢ ( ( 2 ↑𝑐 ( 2 logb 9 ) ) ∈ ℂ → ( ( 2 ↑𝑐 ( 2 logb 9 ) ) ↑𝑐 ( 1 / 2 ) ) = ( √ ‘ ( 2 ↑𝑐 ( 2 logb 9 ) ) ) ) | |
| 22 | 20 21 | ax-mp | ⊢ ( ( 2 ↑𝑐 ( 2 logb 9 ) ) ↑𝑐 ( 1 / 2 ) ) = ( √ ‘ ( 2 ↑𝑐 ( 2 logb 9 ) ) ) |
| 23 | 5 17 22 | 3eqtri | ⊢ ( ( √ ‘ 2 ) ↑𝑐 ( 2 logb 9 ) ) = ( √ ‘ ( 2 ↑𝑐 ( 2 logb 9 ) ) ) |
| 24 | 2ne0 | ⊢ 2 ≠ 0 | |
| 25 | 1ne2 | ⊢ 1 ≠ 2 | |
| 26 | 25 | necomi | ⊢ 2 ≠ 1 |
| 27 | eldifpr | ⊢ ( 2 ∈ ( ℂ ∖ { 0 , 1 } ) ↔ ( 2 ∈ ℂ ∧ 2 ≠ 0 ∧ 2 ≠ 1 ) ) | |
| 28 | 1 24 26 27 | mpbir3an | ⊢ 2 ∈ ( ℂ ∖ { 0 , 1 } ) |
| 29 | 9cn | ⊢ 9 ∈ ℂ | |
| 30 | 9re | ⊢ 9 ∈ ℝ | |
| 31 | 9pos | ⊢ 0 < 9 | |
| 32 | 30 31 | gt0ne0ii | ⊢ 9 ≠ 0 |
| 33 | eldifsn | ⊢ ( 9 ∈ ( ℂ ∖ { 0 } ) ↔ ( 9 ∈ ℂ ∧ 9 ≠ 0 ) ) | |
| 34 | 29 32 33 | mpbir2an | ⊢ 9 ∈ ( ℂ ∖ { 0 } ) |
| 35 | cxplogb | ⊢ ( ( 2 ∈ ( ℂ ∖ { 0 , 1 } ) ∧ 9 ∈ ( ℂ ∖ { 0 } ) ) → ( 2 ↑𝑐 ( 2 logb 9 ) ) = 9 ) | |
| 36 | 28 34 35 | mp2an | ⊢ ( 2 ↑𝑐 ( 2 logb 9 ) ) = 9 |
| 37 | 36 | fveq2i | ⊢ ( √ ‘ ( 2 ↑𝑐 ( 2 logb 9 ) ) ) = ( √ ‘ 9 ) |
| 38 | sqrt9 | ⊢ ( √ ‘ 9 ) = 3 | |
| 39 | 23 37 38 | 3eqtri | ⊢ ( ( √ ‘ 2 ) ↑𝑐 ( 2 logb 9 ) ) = 3 |