Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

Pages: **1**

**shivusuja****Member**- Registered: 2006-09-14
- Posts: 56

please help me out

IF a sin x +b cos x = c . Prove that a cos b sinx=sq root(a sqared+b squared+c squared)

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,844

hi shivusuja

where

Do a similar thing with the second expression leading to cos(x + alpha)

Now you can use sin^2 + cos^2 = 1 to finish the proof.

Note: But I ended up with minus c^2 not plus.

Bob

Children are not defined by school ...........The Fonz

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**shivusuja****Member**- Registered: 2006-09-14
- Posts: 56

thank you . may be the text book print is wrong.

Offline

Pages: **1**