AB? =? AC? =? 6,
Through point a as AD⊥BC in d,
AD? =? h,
BD? =? DC? =? x,
Judging from the title:
xh= 12,
From Pythagorean Theorem: X? +? h^? =? 36,
Put xh? =? 24 into x? +? h^? =? 36 Must:
x^? +? h^? =? 3xh/2,
∴2h^? -? 3xh? -? 2x^? =? 0,
Divide both sides by x:
2(h/x)^? -? 3h/x? -? 2? =? 0,
Take (h/x) as a whole, and get it by finding the root formula:
h/x? =? 2 (I will omit the negation)
∴ The tangent of the base angle is 2,
What they did was wrong! )
2. Make a symmetrical point P of point E about AC. Obviously, p is on AD.
Connect PB to AC to f,
EF at this time? +? BF? At the very least,
Number three, number three,
3. In Rt△ABC, ∠ c = 90,
Let the opposite sides of angles a, b and c be a, b and c respectively.
∴sinA? =? Air conditioning?
Tana? =? a/b
∵ Sina Yi? +? Tana 1 =5
∴c/a? +? b/a? =? 5,
∴b? +? c? =? 5a,
From Pythagorean Theorem:
a^? +? b^? =? c^,
Play b? +? c? =? Replace a with 5a? +? b^? =? Merge and simplify:
13(b/c)^? +? b/c? -? 12? =? 0,
Considering b/c as a whole, it is obtained from the bulbous formula:
b/c? =? 12/ 13,
∴cosA? =? 12/ 13,
4. Solution: ∵ The zeroth power of any non-zero real number is 1.
∴(√3- 1) is 1.
The answer is detailed enough!