4. (1 point) Which expression is equivalent to (sinTheta +cosTheta )^2 sin^2Theta +cos^2Theta b. 2sinTheta cosTheta c. 1+2sinTheta cosTheta d. I

## Step 1: Expand the Expression<br />### Expand $(sin\Theta +cos\Theta )^{2}$ using the formula $(a+b)^2 = a^2 + 2ab + b^2$. This gives us $sin^2\Theta + 2sin\Theta cos\Theta + cos^2\Theta$.<br /><br />## Step 2: Apply the Pythagorean Identity<br />### Recall the Pythagorean identity: $sin^2\Theta + cos^2\Theta = 1$. Substitute this into the expanded expression from Step 1. This simplifies the expression to $1 + 2sin\Theta cos\Theta$.