Answer:
1) cos (3x)
2) ![\frac{-(1-\sqrt{3})^{2}}{2}](https://tex.z-dn.net/?f=%5Cfrac%7B-%281-%5Csqrt%7B3%7D%29%5E%7B2%7D%7D%7B2%7D)
Step-by-step explanation:
Given expression:
cos(7x)cos(4x)+sin(7x)sin(4x)
By using the trigonometric identity
cos(a)cos(b) + sin(a)sin(b) = cos(a-b)
we have:
cos(7x)cos(4x)+sin(7x)sin(4x) = cos(7x - 4x)
= cos(3x)!
part 2:
tan (-π/12)
by using property tan(-x)= - tan(x)
=-tan(π/12)
= - tan(π/6 / 2)
Using tan(x/2) = ![\sqrt{\frac{1 - cos(x)}{1+cos(x)} }](https://tex.z-dn.net/?f=%5Csqrt%7B%5Cfrac%7B1%20-%20cos%28x%29%7D%7B1%2Bcos%28x%29%7D%20%7D)
= - ![\sqrt{\frac{1 - cos(pi/6)}{1+cos(pi/6)} }](https://tex.z-dn.net/?f=%5Csqrt%7B%5Cfrac%7B1%20-%20cos%28pi%2F6%29%7D%7B1%2Bcos%28pi%2F6%29%7D%20%7D)
cos π/6 = ![\frac{\sqrt{3} }{2}](https://tex.z-dn.net/?f=%5Cfrac%7B%5Csqrt%7B3%7D%20%7D%7B2%7D)
= -![\sqrt{\frac{1-\frac{\sqrt{3} }{2} }{1+\frac{\sqrt{3} }{2} } }](https://tex.z-dn.net/?f=%5Csqrt%7B%5Cfrac%7B1-%5Cfrac%7B%5Csqrt%7B3%7D%20%7D%7B2%7D%20%7D%7B1%2B%5Cfrac%7B%5Csqrt%7B3%7D%20%7D%7B2%7D%20%7D%20%7D)
= - ![\sqrt{7-4\sqrt{3} }](https://tex.z-dn.net/?f=%5Csqrt%7B7-4%5Csqrt%7B3%7D%20%7D)
= - 2+![\sqrt{3}](https://tex.z-dn.net/?f=%5Csqrt%7B3%7D)
= ![-\frac{(1-\sqrt{3}) ^{2} }{2}](https://tex.z-dn.net/?f=-%5Cfrac%7B%281-%5Csqrt%7B3%7D%29%20%5E%7B2%7D%20%7D%7B2%7D)
!
.008 is the answer you are looking for :)
Answer: 105 degrees
Step-by-step explanation:
so, since it is a parallelogram, adjacent angles are equal. so, we know that angle S and angle U are equal. that means we can subtract 150 from the 360 degrees of the full parallelogram. so, that leaves 210 degrees to work with. since it is shared amongst the other two equal angles, we just divide it by 2. so, that's how we get the answer.
Answer:
A is 15, B is 75, and C is 30
Step-by-step explanation: