What is the general solution for -20cos^2(x)-36cos(x)=16 ?

The general solution for -20cos^2(x)-36cos(x)=16 is x=pi+2pin,x=2.49809…+2pin,x=-2.49809…+2pin

English

Español

Português

Français

Deutsch

Italiano

Русский

中文(简体)

한국어

日本語

Tiếng Việt

עברית

العربية

Popular >

-20cos^2(x)-36cos(x)=16

- 20 cos^{2} (x) - 36 cos (x) = 16

x = π + 2 πn, x = 2.49809 \dots + 2 πn, x = - 2.49809 \dots + 2 πn

Solution steps

- 20 cos^{2} (x) - 36 cos (x) = 16

Solve by substitution

cos (x) = - 1, cos (x) = - \frac{4}{5}

cos (x) = - 1 : x = π + 2 πn

cos (x) = - \frac{4}{5} : x = arccos (- \frac{4}{5}) + 2 πn, x = - arccos (- \frac{4}{5}) + 2 πn

Combine all the solutions

x = π + 2 πn, x = arccos (- \frac{4}{5}) + 2 πn, x = - arccos (- \frac{4}{5}) + 2 πn

Show solutions in decimal form

x = π + 2 πn, x = 2.49809 \dots + 2 πn, x = - 2.49809 \dots + 2 πn

cos (3 x) = \frac{1}{2}, 0 \leq x < 2 π

- sin (x) - 2 cos (x) = 1

tan (2 x) + 1 = sec (2 x), 0 \leq x \leq 2 π

3 sin^{2} (θ) - 8 sin (θ) + 5 = 0

8 cos (x) - 4 = 0

What is the general solution for -20cos^2(x)-36cos(x)=16 ?
The general solution for -20cos^2(x)-36cos(x)=16 is x=pi+2pin,x=2.49809…+2pin,x=-2.49809…+2pin