Question

请教几道数学题 谢谢

1. Find the value of parameter a such that
f(x)=(5-a)x平方-2(1-a)x=2-2a
is negative for any real number x.

2. Solve the equation:
log以(x-1)为底（3x平方-4x-11）的倒数=2

算出x=-2或3
用舍去一个吗？

3.(1) Find the equation of lines passing through the origin and tangent to the circle having equation x平方+y平方+2倍根下3乘以(x+y)+7=0.
(2) Determine the angle enclosed by the tangent lines

4.Solve the system of inequality:
0<cot x<1

5.Two sides of a triangl are 5cm and 9cm long. The ratio of the opposite angels is 1:3. Determine the angles and the length of the third side of the triangle.

Answer 1

先帮你翻译,你自己拿去一个个提问~~这样任务量减少了,会有更多人愿意回答~~

f(x)=(5-a)x²-2(1-a)x+(2-2a)
确定参数a,使得函数f(x)对于任意x,它的值恒为正.

解方程:
log(x-1) 1/(3x²-4x-11)=2 (其中x-1是底)

圆C的方程是:x²+y²+2(根号3)(x+y)+7=0
直线L过原点且与圆相切
(1)求直线L的方程
(2)确定这两条切线间的夹角

解不等式:
0<cot x<1

已知三角形的两边长分别是5cm,9cm.这两条边所对的角的度数比是1:3
试确定三角形的各内角度数,并求出第三边的长度~

Answer 2

1. a<1或a>11/3
2. 舍去x=-2
3.（1）2y=(3+或-根号5)x
（2）60°
4.x∈[kπ+π/4，kπ+π/2](kπ∈Z)