Step-by-step explanation:
We know that
cos 2x = 2cos²x - 1
So we have
Substituting
Answer: 67°
Step-by-step explanation:
Complementary angle refers to the angle that when added together will be equal to 90°.
Let the measurement of the angle's complement be x.
Therefore, the angles are x and 2x + 21. Since it's a complementary angle, therefore,
x + 2x + 21 = 90
3x + 21 = 90
3x = 90 - 21
3x = 69
x = 69°/3
x = 23°
Therefore, the angle will be:
= 2x + 21
= 2(23°) + 21°
= 46° + 21°
= 67°
The angle is 67°.
Answer:
6 and -14
Step-by-step explanation:
Area of the triangle = 1/2 ab
42 = 1/2 (x)(x+8)
42 *2 = x(x+8)
84 = x²+8x
x²+8x-84 = 0
x²+14x-6x-84 = 0
x(x+14)-6(x+14) = 0
x-6 = 0 and x+14 = 0
x = 6 and -14
Hence the values of x are 6 and -14