Jika salah satu diantara 3 soal ada yg tau tolong dijawab ya..

10. trigonometri

tan x = 1/t
tan x = y/x
x = t, y = 1 --> r² = x²+y²
r² = t²+ 1
r = √(t²+1)
sin x = y/r = 1/√(t²+1)

cos 2x = 1- 2 sin² x
cos 2x = 1 - 2 (1/(t² +1))
cos 2x = 1- 2 /(t²+1)
cos 2x = (t²+ 1 - 2)/(t² + 1)
cos 2x = (t²- 1)/(t² + 1)

11.  jarak Anak ke titik lepas balon =x = 20 m
h(t)= 10t - t²
maksimum jika h ' (t)= 0
10- 2t= 0
t = 5
hmaksimum= h = 10(5)-(5)² = 50 - 25  =25 m

jarak Anak ke balon= r
r² = h²+ x²
r² = 25²+ 20² = 1025
r = √1025
r= 5√41 m