# Trig

posted by .

Prove (3cosθ-4sinθ)^2+(4cosθ+3sinθ)^2=25

• Trig -

square both terms...

9cos^2+4sin^2-24cossin+16cos^2+24cossin+9sin^2=

9(cos^2+sin^2)+16(cos^2+sin^2)=
and you can finish it.

## Similar Questions

1. ### Math - Calculus

The identity below is significant because it relates 3 different kinds of products: a cross product and a dot product of 2 vectors on the left side, and the product of 2 real numbers on the right side. Prove the identity below. | a …
2. ### math

Prove the following identities: a) (cosec θ + cotθ)(cosecθ - cotθ) = cotθtanθ b) 2/(1 + sinθ) + 1/(1- sinθ) = (3sec^2)θ - tanθcosecθ I basically just have to prove Left HandSide …
3. ### Math - Trig Substitution

How can I solve the integral of x^3√(9-x^2) dx using trigonometric substitution?
4. ### trig

The terminal side of θ lies on a given line in the specified quadrant. Find the values of the six trigonometric functions of θ by finding a point on the line. Line: (55/48)x Quadrant:III sin(θ)= cos(θ)= tan(θ)= …
5. ### Math

1. Find the exact value of 2tan pi/12 / 1-tan^2 pi/12 root 3/3?
6. ### Trig

Given that tan θ = - (√3/8) and θ is in QII, find the exact value of a. r = b. csc θ c. cos θ d. cot θ
7. ### Trig

Given that csc θ = -4 and tan θ > 0, find the exact value of a. x b. sin θ c. cos θ d. r e. sec θ f. cot θ
8. ### Precalc/Trig

Sorry there are quite a few problems, but I just need to know if these are correct (and if they aren't, where I went wrong): 1. Solve these equations. tanθ = -√3 θ = 2π/3 + kπ θ = 5π/3 + kπ …
9. ### Statistics

θ=0.5 θ=1 θ=2 θ=3 λ = 2 θ = 0.5 μ = 0.5 σ = 0.5 θ=0.5 0 2 1 0.270670566 2 0.036631278 3 0.004957504 4 0.000670925 5 9.07999E-05 draw the graph for θ=1 θ=2 θ=3 The first θ=0.5 …
10. ### Opt math URGENT

prove that : cos^3(θ)sin^2(θ)=1/16[2cos(θ)-3cos(θ)-5cos(θ)]

More Similar Questions