Posted by **Abby** on Tuesday, February 23, 2010 at 7:00pm.

1) Solve the equation

sinx(sinx+1) = 0

I am having trouble with the first step. Could I do sin x^2 + 1 =0?

- Pre-cal -
**MathMate**, Tuesday, February 23, 2010 at 8:31pm
Using distributive property of multiplication over addition:

p(p+1)=x²+x

If p=sin(x), then

sin(x)(sin(x)+1)=sin²(x)+sin(x)

However, this particular problem does not require the expression to be expanded.

In fact, if

p(p+1)=0, it means that either p=0, or p+1=0.

Substitute p=sin(x), we get:

sin(x)=0 .......(1) or

sin(x)+1=0.......(2)

Solve for x in each of the two cases. The answer is the union of the two sets of answers.

## Answer this Question

## Related Questions

- Trig Help - Prove the following: [1+sinx]/[1+cscx]=tanx/secx =[1+sinx]/[1+1/sinx...
- calculus - Could someone check my reasoning? thanx Find the derivative of the ...
- math - the problem is 2cos^2x + sinx-1=0 the directions are to "use an identity ...
- Math Help - Hello! Can someone please check and see if I did this right? Thanks...
- Trigonometic - Solving Trigonometic Equations solve for x and give the answers ...
- Trig........ - I need to prove that the following is true. Thanks (cosx / 1-sinx...
- Trigonometry. - ( tanx/1-cotx )+ (cotx/1-tanx)= (1+secxcscx) Good one! ...
- Math (trigonometric identities) - I was given 21 questions for homework and I ...
- Math - Pre- Clac - Prove that each of these equations is an identity. A) (1 + ...
- Math/Calculus - Please take a look at my work below and provide a good critique...

More Related Questions