Question

If x tan² 120° + 4cos2 150° = 9, then x is​

Answer 1

Answer:

-2

Step-by-step explanation:

tan² (∅)= [1+cos(2∅) ]/ [1−cos(2∅) ]

cos²(∅)=  (1/2)[1+cos (2∅)]

so,

x[1+cos{2(120°)}]/[1-cos{2(120°)}] + (4)(1/2)[1+cos{2(150°)}] = 9

x[1.5/-.5]+(4)[1.5]=9

x(-3)+3=9

-3x=6

x=-2

​

Answer 2

Answer:

2

Step-by-step explanation:

x tan^2 120 degrees +4 cos^2 150 degrees =9

x tan^2(180 degree - 60 degree)+4 cos^2(180 degree - 30 degree)=9

x(- tan^2 60 degree)+4(- cos^2 30 degree)=9

x(-root 3)^2 + 4(-root 3/2)^2=9

x(3)+4(3/4)=9

3x+3=9

3x=9-3

3x=6

x=6/3

x=2

Hope it is helpful to you.....